description: Lord Omkar would like to have a tree with n nodes (3 ≤ n ≤ 10^5) and has asked his disciples to construct the tree. However, Lord Omkar has created m (1 ≤ m < n) restrictions to ensure that the tree will be as heavenly as possible. 
  
  A tree with n nodes is an connected undirected graph with n nodes and n-1 edges. Note that for any two nodes, there is exactly one simple path between them, where a simple path is a path between two nodes that does not contain any node more than once.
  
  Here is an example of a tree: 
  
  <image>
  
  A restriction consists of 3 pairwise distinct integers, a, b, and c (1 ≤ a,b,c ≤ n). It signifies that node b cannot lie on the simple path between node a and node c. 
  
  Can you help Lord Omkar and become his most trusted disciple? You will need to find heavenly trees for multiple sets of restrictions. It can be shown that a heavenly tree will always exist for any set of restrictions under the given constraints.
  
  Input
  
  Each test contains multiple test cases. The first line contains the number of test cases t (1 ≤ t ≤ 10^4). Description of the test cases follows.
  
  The first line of each test case contains two integers, n and m (3 ≤ n ≤ 10^5, 1 ≤ m < n), representing the size of the tree and the number of restrictions.
  
  The i-th of the next m lines contains three integers a_i, b_i, c_i (1 ≤ a_i, b_i, c_i ≤ n, a, b, c are distinct), signifying that node b_i cannot lie on the simple path between nodes a_i and c_i. 
  
  It is guaranteed that the sum of n across all test cases will not exceed 10^5.
  
  Output
  
  For each test case, output n-1 lines representing the n-1 edges in the tree. On each line, output two integers u and v (1 ≤ u, v ≤ n, u ≠ v) signifying that there is an edge between nodes u and v. Given edges have to form a tree that satisfies Omkar's restrictions.
  
  Example
  
  Input
  
  
  2
  7 4
  1 2 3
  3 4 5
  5 6 7
  6 5 4
  5 3
  1 2 3
  2 3 4
  3 4 5
  
  
  Output
  
  
  1 2
  1 3
  3 5
  3 4
  2 7
  7 6
  5 1
  1 3
  3 2
  2 4
  
  Note
  
  The output of the first sample case corresponds to the following tree: 
  
  <image> For the first restriction, the simple path between 1 and 3 is 1, 3, which doesn't contain 2. The simple path between 3 and 5 is 3, 5, which doesn't contain 4. The simple path between 5 and 7 is 5, 3, 1, 2, 7, which doesn't contain 6. The simple path between 6 and 4 is 6, 7, 2, 1, 3, 4, which doesn't contain 5. Thus, this tree meets all of the restrictions.
  
  The output of the second sample case corresponds to the following tree: 
  
  <image>
solution: 
  import java.io.*;
          import java.util.Arrays;
          import java.util.*;
          import java.util.Scanner;
          import java.util.StringTokenizer;
  
  
  
  public class copy {
  
  
      public static boolean checker(long[] arr, long K, long diff) {
          long collect = 0;
          for (int i = 0; i < arr.length; i++) {
              if (arr[i] > diff)
                  collect += arr[i] - diff;
          }
  
          if (collect >= K)
              return true;
          else
              return false;
      }
  
      public static long search(long[] arr, long K, long R) {
          long l = 0;
          long r = R;
  
          while (l <= r) {
              long mid = (l + r) / 2;
  
              if (checker(arr, K, mid)) {
                  if (checker(arr, K, mid + 1))
                      l = mid + 1;
                  else
                      return mid;
              } else
                  r = mid - 1;
          }
          return -1;
      }
  
      static void sieveOfEratosthenes(int n, ArrayList<Integer> arr, ArrayList<Integer> arr1) {
          // Create a boolean array
          // "prime[0..n]" and
          // initialize all entries
          // it as true. A value in
          // prime[i] will finally be
          // false if i is Not a
          // prime, else true.
          boolean prime[] = new boolean[n + 1];
          for (int i = 0; i <= n; i++)
              prime[i] = true;
  
          for (int p = 2; p * p <= n; p++) {
              // If prime[p] is not changed, then it is a
              // prime
              if (prime[p] == true) {
  
                  // Update all multiples of p
                  for (int i = p * p; i <= n; i += p)
                      prime[i] = false;
              }
          }
  
          // Print all prime numbers
          int x = 0;
          for (int i = 2; i <= n; i++) {
              if (prime[i] == true) {
  
                  arr.add(i);
  
  
              }
  
          }
          System.out.println(arr.size());
      }
  
      public static boolean check(String s, int K, char ch) {
          ArrayList<Integer> arr = new ArrayList<>();
          for (int i = 0; i < s.length(); i++) {
              if (s.charAt(i) == ch)
                  arr.add(i);
          }
  //        if(K==1 && ch=='z')
  //            System.out.println(arr);
          if (arr.size() == 0)
              return false;
          if (arr.get(0) >= K)
              return false;
          if (s.length() - 1 - arr.get(arr.size() - 1) >= K)
              return false;
          for (int i = 1; i < arr.size(); i++) {
              if (arr.get(i) - arr.get(i - 1) > K)
                  return false;
          }
          return true;
      }
  
      public static int check(long N) {
          int sum = 0;
          while (N > 0) {
              sum += N % 10;
              N = N / 10;
          }
          return sum;
  
      }
  
      public static long call(long N) {
          long l = 1;
          long r = (long) Math.floor(Math.sqrt(N));
          while (l <= r) {
              long mid = (l + r) / 2;
              double left = N / (double) (mid) - mid;
              int right = check(mid);
              System.out.println(mid + " " + left + " " + right);
              if (mid == 10)
                  System.out.println(left + " " + right);
              if (left > right)
                  l = mid + 1;
              else if (right > left)
                  r = mid - 1;
              else
                  return mid;
          }
          return -1;
      }
  
      public static int path(ArrayList<ArrayList<Integer>> arr, int X, int parent, int[] gold, PriorityQueue<Integer> pq) {
          int max = 0;
          ArrayList<Integer> ch = new ArrayList<>();
          for (int i : arr.get(X)) {
              if (i != parent) {
                  ch.add(path(arr, i, X, gold, pq));
              }
          }
          Collections.sort(ch, Collections.reverseOrder());
          for (int i = 1; i < ch.size(); i++)
              pq.add(ch.get(i));
  
  
          if (ch.size() == 0)
              return gold[X];
          else
              return ch.get(0) + gold[X];
  
      }
  
      public static long fac(long N, long mod) {
          if (N == 0)
              return 1;
          if(N==1)
              return 1;
          return ((N % mod) * (fac(N - 1, mod) % mod)) % mod;
      }
  
      public static String form(char ch, int freq) {
          String s = "";
          for (int i = 1; i <= freq; i++)
              s += ch;
          return s;
      }
  
      static long power(long x, long y, long p) {
  
          // Initialize result
          long res = 1;
  
          // Update x if it is more than or
          // equal to p
          x = x % p;
  
          while (y > 0) {
  
              // If y is odd, multiply x
              // with result
              if (y % 2 == 1)
                  res = (res * x) % p;
  
              // y must be even now
              y = y >> 1; // y = y/2
              x = (x * x) % p;
          }
  
          return res;
      }
  
      // Returns n^(-1) mod p
      static long modInverse(long n, long p) {
          return power(n, p - 2, p);
      }
  
      // Returns nCr % p using Fermat's
      // little theorem.
      static long nCrModPFermat(long n, long r,
                                long p) {
  
          if (n < r)
              return 0;
          // Base case
          if (r == 0)
              return 1;
  
          // Fill factorial array so that we
          // can find all factorial of r, n
          // and n-r
  
  
  //        System.out.println(modInverse(fac(r,p),p));
  //        System.out.println(modInverse(fac(n-r,p),p));
          return ((fac(n, p) % p * (modInverse(fac(r, p), p)
                  % p)) % p * (modInverse(fac(n - r, p), p)
                  % p)) % p;
      }
  
      public static boolean check(long[] arr, long time, int M) {
          long sum = 0;
          int count = 0;
          for (int i = 0; i < arr.length; i++) {
              sum += arr[i];
              if (sum >= time) {
                  ++count;
                  sum = 0;
              }
          }
  
          if (sum >= time)
              ++count;
  
          return count >= M;
      }
  
      public static int check(ArrayList<Integer> arr, ArrayList<Integer> arr2) {
          int l = 0, r = 0, ans = 0;
          while (l < arr.size() && r < arr2.size()) {
              if (arr.get(l) < arr2.get(r))
                  ++l;
              else if (arr.get(l) > arr2.get(r))
                  ++r;
              else {
                  ++ans;
                  ++l;
                  ++r;
              }
          }
          return ans;
      }
  
  
      public static int find(int[] parent, int x) {
          if (parent[x] == x)
              return x;
          return find(parent, parent[x]);
      }
  
      public static void merge(int[] parent, int[] rank, int x, int y) {
          int x1 = find(parent, x);
          int y1 = find(parent, y);
          if (rank[x1] > rank[y1]) {
              parent[y1] = x1;
  
          } else if (rank[y1] > rank[x1]) {
              parent[x1] = y1;
          } else {
              parent[y1] = x1;
              rank[x1]++;
          }
      }
  
      public static int check(ArrayList<ArrayList<Integer>> arr, int e1, int e2, int N) {
          boolean[] visited = new boolean[N];
          visited[0] = true;
          int[] dist = new int[N];
          Queue<Integer> queue = new LinkedList<>();
          queue.add(0);
          Arrays.fill(dist, -1);
          dist[0] = 0;
          while (queue.size() > 0) {
              int x = queue.poll();
              for (int i : arr.get(x)) {
                  if (!visited[i] || (e1 == x && e2 == i)) {
                      System.out.println(x + " " + dist[x]);
                      dist[i] = dist[x] + 1;
                      visited[i] = true;
                      queue.add(i);
                  }
              }
  
          }
  
  
          return dist[N - 1];
      }
  
      static int N;
  
      static void rotate90Clockwise(String a[][]) {
  
          // Traverse each cycle
          for (int i = 0; i < N / 2; i++) {
              for (int j = i; j < N - i - 1; j++) {
  
                  // Swap elements of each cycle
                  // in clockwise direction
                  String temp = a[i][j];
                  a[i][j] = a[N - 1 - j][i];
                  a[N - 1 - j][i] = a[N - 1 - i][N - 1 - j];
                  a[N - 1 - i][N - 1 - j] = a[j][N - 1 - i];
                  a[j][N - 1 - i] = temp;
              }
          }
      }
  
  
      public static void moves(String s, int i, int[] movx, int[] movy, int x, int y) {
          if (i >= s.length())
              return;
          //System.out.println(x+" hello "+y);
          if (s.charAt(i) == 'L') {
              movy[i] = y;
              movx[i] = x - 1;
              moves(s, i + 1, movx, movy, x - 1, y);
          } else if (s.charAt(i) == 'R') {
              movy[i] = y;
              movx[i] = x + 1;
              moves(s, i + 1, movx, movy, x + 1, y);
          } else if (s.charAt(i) == 'U') {
              movy[i] = y + 1;
              movx[i] = x;
              moves(s, i + 1, movx, movy, x, y + 1);
          } else {
              movy[i] = y - 1;
              movx[i] = x;
              moves(s, i + 1, movx, movy, x, y - 1);
          }
  
      }
  
  
      public static boolean check(String s, int i, int x, int y, int obsx, int obsy) {
          if (i >= s.length()) {
              if (x == 0 && y == 0)
                  return true;
              return false;
          }
          boolean status1 = false, status2 = false, status3 = false, status4 = false;
          //System.out.println(x+" "+y+" "+obsx+" "+obsy+" "+s.charAt(i));
          if (s.charAt(i) == 'L') {
              if (x - 1 == obsx && y == obsy)
                  status1 = check(s, i + 1, x, y, obsx, obsy);
              else
                  status1 = check(s, i + 1, x - 1, y, obsx, obsy);
              //moves(s,i+1,movx,movy,x-1,y);
          } else if (s.charAt(i) == 'R') {
              if (x + 1 == obsx && y == obsy)
                  status2 = check(s, i + 1, x, y, obsx, obsy);
              else
                  status2 = check(s, i + 1, x + 1, y, obsx, obsy);
              //moves(s,i+1,movx,movy,x+1,y);
          } else if (s.charAt(i) == 'U') {
              if (y + 1 == obsy && x == obsx)
                  status3 = check(s, i + 1, x, y, obsx, obsy);
              else
                  status3 = check(s, i + 1, x, y + 1, obsx, obsy);
              //moves(s,i+1,movx,movy,x,y-1);
          } else {
              if (y - 1 == obsy && x == obsx)
                  status4 = check(s, i + 1, x, y, obsx, obsy);
              else
                  status4 = check(s, i + 1, x, y - 1, obsx, obsy);
          }
          return status1 || status2 || status3 || status4;
      }
  
      public static int mergeAndCount1(div[] arr, int l,
                                       int m, int r,int[] answer) {
  
          // Left subarray
  
          div[] left = Arrays.copyOfRange(arr, l, m + 1);
  
          // Right subarray
          div[] right = Arrays.copyOfRange(arr, m + 1, r + 1);
  
          int i = 0, j = 0, k = l, swaps = 0;
          for(int x=0;x<right.length;x++)
              answer[right[x].y]+=binse(left,right[x].x,left.length);
  
          while (i < left.length && j < right.length) {
              if (left[i].x <= right[j].x)
                  arr[k++] = left[i++];
              else {
                  //answer[right[j].y]+=binse(left,right[j].x,left.length);
                  arr[k++] = right[j++];
  
              }
          }
          while (i < left.length)
              arr[k++] = left[i++];
          while (j < right.length)
              arr[k++] = right[j++];
  //        System.out.println(l+" "+r);
  //        for(i=0;i<answer.length;i++)
  //            System.out.print(answer[i]+" ");
  //        System.out.println();
          return swaps;
      }
  
      // Merge sort function
      public static int mergeSortAndCount(div[] arr, int l,
                                          int r,int[] answer) {
  
          // Keeps track of the inversion count at a
          // particular node of the recursion tree
          int count = 0;
  
          if (l < r) {
              int m = (l + r) / 2;
  
              // Total inversion count = left subarray count
              // + right subarray count + merge count
  
              // Left subarray count
              count += mergeSortAndCount(arr, l, m,answer);
  
              // Right subarray count
              count += mergeSortAndCount(arr, m + 1, r,answer);
  
              // Merge count
              count += mergeAndCount1(arr, l, m, r,answer);
          }
  
          return count;
      }
  
  
      public static boolean checker(String s1, String s2, int[] arr, int mid) {
          String s = "";
          int N = s1.length();
          boolean[] visited = new boolean[N];
          for (int i = 0; i <= mid; i++)
              visited[arr[i] - 1] = true;
          for (int i = 0; i < N; i++) {
              if (!visited[i])
                  s += s1.charAt(i);
          }
  
          int l = 0, index = -1;
          while (l < s2.length()) {
              if (s.indexOf(s2.charAt(l), index + 1) == -1)
                  return false;
              else {
                  index = s.indexOf(s2.charAt(l), index + 1);
                  ++l;
              }
          }
  
          return true;
      }
  
      public static int check(ArrayList<Integer> possible, int X, int start) {
          int l = start, r = possible.size() - 1;
  
          while (l <= r) {
              int mid = (l + r) / 2;
              if (possible.get(mid) > X) {
                  if (mid - 1 >= start && possible.get(mid - 1) > X)
                      r = mid - 1;
                  else
                      return mid;
              } else
                  l = mid + 1;
          }
  
          return -1;
      }
  
  
      public static int binse(div[] arr, int X, int N) {
          int l = 0, r = N - 1;
  
          if(arr[N-1].x<=X)
              return N;
          if(arr[0].x>X)
              return 0;
          while (l <= r) {
              int mid = (l + r) / 2;
  //            if(N==2)
  //            {
  //                System.out.println(arr[mid].x+" hello "+X);
  //            }
              if(arr[mid].x<=X)
              {
                  if(mid+1<N && arr[mid+1].x<=X)
                      l=mid+1;
                  else
                  {
                      //System.out.println(X+" "+mid);
  
                      return mid+1;
                  }
              }
  
              else
                  r=mid-1;
          }
          return -1;
      }
  
  
      public static long dp(long[][] dp, int X, int[] arr, int index, long mod) {
          //System.out.println(index+" "+X);
          if (dp[index][X] != -1)
              return dp[index][X];
          int index1 = index + 1;
          int plus = (X - arr[index1] + 10) % 10;
          long ans = dp(dp, plus, arr, index - 1, mod) % mod;
          for (int i = 0; i < 10; i++) {
              if ((arr[index1] * i) % 10 == X)
                  ans = (ans % mod + dp(dp, i, arr, index - 1, mod) % mod) % mod;
          }
  
          dp[index][X] = ans;
          return ans;
  
  
      }
  
      public static long gcd(long a, long b) {
          if (b == 0)
              return a;
  
          return gcd(b, a % b);
      }
  
      public static int check(int x, ArrayList<ArrayList<Integer>> arr, int parent, int dist, long[] ans, int[] child) {
          ans[0] += dist;
          int c = 0;
          for (int i : arr.get(x)) {
              if (i != parent)
                  c += check(i, arr, x, dist + 1, ans, child);
          }
  
          child[x] = c + 1;
          return c + 1;
      }
  
      public static void check(int x, int parent, ArrayList<ArrayList<Integer>> arr, int[] child, long[] ans) {
          ans[x] = ans[parent] - (child[x]) + (arr.size() - child[x]);
  
          for (int i : arr.get(x)) {
              if (i != parent) {
                  check(i, x, arr, child, ans);
              }
          }
      }
  
      public static void leftRotatebyOne(int arr[], int n) {
          int i, temp;
          temp = arr[0];
          for (i = 0; i < n - 1; i++)
              arr[i] = arr[i + 1];
          arr[n - 1] = temp;
      }
  
      public static void tick(char[][] ch, int N, int M, int x, int y, int k, int[][] copy) {
  
          int c = 1, size = 0;
          //System.out.println(x+" "+y);
          while (x - c >= 0 && y - c >= 0 && y + c < M && ch[x - c][y - c] == '*' && ch[x - c][y + c] == '*') {
              ++size;
  
              ++c;
  
          }
          //System.out.println(size);
          c -= 1;
          while (c >= 0) {
  
              copy[x - c][y - c] = Math.max(copy[x - c][y - c], size);
              copy[x - c][y + c] = Math.max(copy[x - c][y + c], size);
  
              --c;
          }
  
  
      }
  
      public static long dp(ArrayList<Integer> arr,HashMap<Integer,Long> hp)
      {
          if(arr.size()==0)
              return 0;
          long[]dp=new long[arr.size()];
          dp[0]=hp.get(arr.get(0))*arr.get(0);
          if(arr.size()==1)
              return dp[0];
          dp[1]=Math.max(arr.get(1)*(hp.get(arr.get(1))),arr.get(0)*(hp.get(arr.get(0))));
          for(int i=2;i<arr.size();i++)
          {
              int X=arr.get(i);
              dp[i]=Math.max(X*(hp.get(X))+dp[i-2],dp[i-1]);
              dp[i]=Math.max(dp[i],dp[i-2]+X*hp.get(X));
          }
  //        for(int i=0;i<arr.size();i++)
  //            System.out.println(dp[i]);
  
          return dp[arr.size()-1];
      }
  
      static int power(int x, int y, int p)
      {
  
          // Initialize result
          int res = 1;
  
          // Update x if it is more than or
          // equal to p
          x = x % p;
  
          while (y > 0) {
  
              // If y is odd, multiply x
              // with result
              if (y % 2 == 1)
                  res = (res * x) % p;
  
              // y must be even now
              y = y >> 1; // y = y/2
              x = (x * x) % p;
          }
  
          return res;
      }
  
      // Returns n^(-1) mod p
      static int modInverse(int n, int p)
      {
          return power(n, p - 2, p);
      }
  
      // Returns nCr % p using Fermat's
      // little theorem.
      static int nCrModPFermat(int n, int r,
                               int p)
      {
  
          if (n<r)
              return 0;
          // Base case
          if (r == 0)
              return 1;
  
          // Fill factorial array so that we
          // can find all factorial of r, n
          // and n-r
          int[] fac = new int[n + 1];
          fac[0] = 1;
  
          for (int i = 1; i <= n; i++)
              fac[i] = fac[i - 1] * i % p;
  
          return (fac[n] * modInverse(fac[r], p)
                  % p * modInverse(fac[n - r], p)
                  % p)
                  % p;
      }
  
      public static int check(int N,int[] dp)
      {
          if(N==0)
              return 0;
          if(dp[N]!=-1)
              return dp[N];
  
          if(N<10)
              return 1;
          int max=Integer.MAX_VALUE;
          int X=N;
          while(X>0)
          {
              int digit=X%10;
              if(digit!=0)
              {
                  if(dp[N-digit]==-1)
                      max=Math.min(max,check(N-digit,dp));
                  else
                      max=Math.min(max,dp[N-digit]);
              }
              X=X/10;
  
          }
          dp[N]=max+1;
          return max+1;
      }
  
      public static int check(int a,int b,int k,int[][] dp,int index,int N,int[] length)
      {
          if(index>=N)
              return 0;
          if(k==1)
          {
              if(N-index<a || N-index>b)
              {
                  dp[index][k]=0;
                  return 0;
              }
              else
              {
                  dp[index][k]=1;
                  length[index]=N-index;
                  return 1;
              }
          }
          if(dp[index][k]!=-1)
              return dp[index][k];
  
          int ans=0;
          for(int i=a;i<=b;i++)
          {
              if(check(a,b,k-1,dp,index+i,N,length)==1)
              {
                  length[index]=i;
                  ans=1;
              }
          }
          if(ans>=1)
          {
              dp[index][k]=1;
              return 1;
          }
          else
          {
              dp[index][k]=0;
              return 0;
          }
      }
  
      public static long[][] ncr(int n,int r)
      {
          long[][] dp=new long[n+1][r+1];
          for(int i=0;i<=n;i++)
              dp[i][0]=1;
          for(int i=1;i<=n;i++)
          {
              for(int j=1;j<=r;j++)
              {
                  if(j>i)
                      continue;
                  dp[i][j]=dp[i-1][j-1]+dp[i-1][j];
              }
          }
  
          return dp;
  
      }
      public static String answer(String s1,String s2)
      {
          int index=0;
          boolean status=true;
          for(int i=0;i<s2.length();i++)
          {
              if(s1.indexOf(s2.charAt(i),index)==-1)
              {
                  status=false;
              }
              else
              {
                  index=s1.indexOf(s2.charAt(i),index)+1;
              }
          }
          if(status)
              return "automaton";
  
  
          String arr1[]=s1.split("");
          String arr2[]=s2.split("");
          Arrays.sort(arr1);
          Arrays.sort(arr2);
          if(Arrays.equals(arr1,arr2))
              return "array";
  
          HashMap<Character,Integer> hp=new HashMap<>();
          for(int i=0;i<s2.length();i++)
          {
              hp.put(s2.charAt(i),0);
          }
          for(int i=0;i<s2.length();i++)
          {
              if(s1.indexOf(s2.charAt(i),hp.get(s2.charAt(i)))==-1)
              {
                  return "need tree";
              }
              else
              {
                  hp.put(s2.charAt(i),s1.indexOf(s2.charAt(i),hp.get(s2.charAt(i)))+1);
              }
          }
  
          return "both";
  
  
  
      }
      static boolean status=false;
      static int x1=-1,y1=-1;
      public static int dfs(ArrayList<ArrayList<Integer>> arr,int X,int[] ans,int value,int parent)
      {
          int xor=ans[X];
          for(int i:arr.get(X))
          {
              if(i!=parent)
              {
                  int x=dfs(arr,i,ans,value,X);
                  if(x==-1)
                      return -1;
                  if(x==value)
                  {
                      x1=X;
                      y1=i;
                      return -1;
                  }
                  xor=xor^x;
              }
          }
  
  
  
          return xor;
      }
  
      public static boolean prime(long N)
      {
          int c=0;
          for(int i=2;i*i<=N;i++)
          {
              if(N%i==0)
                  ++c;
          }
  
          return c==0;
      }
      static int[] c;
      static boolean sta=true;
      public static int dfs(ArrayList<ArrayList<Integer>> arr,int N,int j,int[] status,boolean[] visited)
      {
          Queue<Integer> queue=new LinkedList<>();
          queue.add(j);
          status[j]=1;
          visited[j]=true;
          int[] color=new int[2];
          while(queue.size()>0)
          {
              int temp=queue.poll();
              if(temp<N)
                  color[status[temp]]++;
              for(int i:arr.get(temp))
              {
                  if(visited[i])
                  {
                      if(status[i]==status[temp])
                          return -1;
                  }
                  else
                  {
                      queue.add(i);
                      status[i]=1-status[temp];
                      visited[i]=true;
                  }
              }
          }
  
          return Math.max(color[0],color[1]);
      }
  
      public static boolean check(String s,int N,long D,long C,long M)
      {
          int index=s.lastIndexOf('D');
          for(int i=0;i<=index;i++)
          {
              if(s.charAt(i)=='D' && D>0)
              {
                  D-=1;
                  C+=M;
              }
              else if(s.charAt(i)=='C' && C>0)
              {
                  C-=1;
              }
              else
                  return false;
          }
  
          return true;
      }
  
      public static div check(long[] prefix,int index,long req,long[] trees,int right) {
          int l = index;
          int r = index;
          long s = 0;
  
          div ans = new div(-1, -1, -1);
          int max = Integer.MAX_VALUE;
          while (r <= right) {
              s += trees[r];
  
              while (s >req && l <= r) {
                  s -= trees[l];
                  ++l;
  
              }
  
              if (s == req) {
                  if (r - l + 1 < max) {
                      max = r - l + 1;
                      ans.x = max;
                      ans.y = l;
                      ans.z = r;
  
                  }
  
              }
  
  
  
              ++r;
  
  
          }
          //System.out.println(max+" "+req);
          return ans;
      }
  
      public static long helper(long[] prefix,int K,long[] trees,int N)
      {
          long max=Long.MAX_VALUE;
          for(int i=0;i<=K;i++)
          {
  
  
  
                  div left=check(prefix,0,i,trees,N-1);
                  if(left.x!=-1)
                  {
                          int rightm=Integer.MAX_VALUE;
                          div right=check(prefix,0,K-i,trees,left.y-1);
                          if(right.x!=-1)
                              rightm=Math.min(rightm,right.x);
  
  
                       right=check(prefix,left.z+1,K-i,trees,N-1);
                      if(right.x!=-1)
                          rightm=Math.min(rightm,right.x);
  
                      if(rightm!=Integer.MAX_VALUE)
                          max=Math.min(max,left.x+rightm);
                  }
  
  
              }
  
  
          if(max==Long.MAX_VALUE)
              return -1;
          return max;
      }
  
  
  
  
  
  
      public static void main(String[] args) throws IOException {
          Reader.init(System.in);
          BufferedWriter output = new BufferedWriter(new OutputStreamWriter(System.out));
  
          int T=Reader.nextInt();
          for(int m=1;m<=T;m++)
          {
              int N=Reader.nextInt();
              int M=Reader.nextInt();
              boolean[] visited=new boolean[N];
              for(int i=0;i<M;i++)
              {
                  int A=Reader.nextInt();
                  int B=Reader.nextInt();
                  int C=Reader.nextInt();
                  visited[B-1]=true;
              }
              int index=-1;
              for(int i=0;i<N;i++)
              {
                  if(!visited[i])
                  {
                      index=i;
                      break;
                  }
              }
              for(int i=0;i<N;i++)
              {
                  if(i==index)
                      continue;
                  output.write((index+1)+" "+(i+1)+"\n");
              }
  
  
  
  
          }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
          output.flush();
  
      }
  }
  
  
  
  class Reader {
      static BufferedReader reader;
      static StringTokenizer tokenizer;
  
      static void init(InputStream input) {
          reader = new BufferedReader(
                  new InputStreamReader(input));
          tokenizer = new StringTokenizer("");
      }
  
      static String next() throws IOException {
          while (!tokenizer.hasMoreTokens()) {
              tokenizer = new StringTokenizer(
                      reader.readLine());
          }
          return tokenizer.nextToken();
      }
  
      static int nextInt() throws IOException {
          return Integer.parseInt(next());
      }
  
      static long nextLong() throws IOException {
          return Long.parseLong(next());
      }
  
      static double nextDouble() throws IOException {
          return Double.parseDouble(next());
      }
  }
  
  class div {
      int x, y,z;
  
      div(int x1, int y1,int z1) {
          x = x1;
          y = y1;
          z=z1;
      }
  }