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.util.*;
  import java.io.*;
  // import java.lang.*;
  // import java.math.*;
  
  public class Codeforces {
      static FastReader sc=new FastReader();
  	static PrintWriter out=new PrintWriter(System.out);
  	static long mod=1000000007;
  	// static long mod=998244353;
  	static int MAX=Integer.MAX_VALUE;
  	static int MIN=Integer.MIN_VALUE;
  	static long MAXL=Long.MAX_VALUE;
  	static long MINL=Long.MIN_VALUE;
  	static ArrayList<Integer> graph[];
  	static long fact[];
  	static StringBuffer sb;
  	public static void main (String[] args) throws java.lang.Exception
  	{
  		// code goes here
  		int t=I();
  		outer:while(t-->0)
  		{
  			int n=I(),m=I();
  			HashSet<Integer> hs=new HashSet<>();
  			for(int i=0;i<m;i++){
  				int a=I(),b=I(),c=I();
  				hs.add(b);
  			}
  			int p=0;
  			for(int i=1;i<=n;i++){
  				if(!hs.contains(i)){
  					p=i;
  					break;
  				}
  			}
  			for(int i=1;i<=n;i++){
  				if(i!=p){
  					out.println(i+" "+p);
  				}
  			}
  		}
  		out.close();
  	}
  	public static class pair
      {
      	int a;
      	int b;
      	public pair(int val,int index)
      	{
      	    a=val;
      	    b=index;
      	}
      }
  	public static class myComp implements Comparator<pair>
  	{
  		//sort in ascending order.
  		public int compare(pair p1,pair p2)
  		{
  			if(p1.a==p2.a)
      	    return 0;
      	    else if(p1.a<p2.a)
      	    return -1;
      	    else
      	    return 1;
  		}
  		//sort in descending order.
  		// public int compare(pair p1,pair p2)
      	// {
      	//     if(p1.a==p2.a)
      	//     return 0;
      	//     else if(p1.a<p2.a)
      	//     return 1;
      	//     else
      	//     return -1;
      	// }
  	}
  	public static long nPr(int n,int r)
  	{
  		long ans=divide(fact(n),fact(n-r),mod);
  		return ans;
  	}
  	public static long nCr(int n,int r)
  	{
  		long ans=divide(fact[n],mul(fact[n-r],fact[r]),mod);
  		return ans;
  	}
  	public static long kadane(long a[],int n)  //largest sum subarray
  	{
  		long max_sum=Long.MIN_VALUE,max_end=0;
  		for(int i=0;i<n;i++){
  			max_end+=a[i];
  			if(max_sum<max_end){max_sum=max_end;}
  			if(max_end<0){max_end=0;}
  		}
  		return max_sum;
  	}
  	public static void DFS(int s,boolean visited[])
  	{
  		visited[s]=true;
  		for(int i:graph[s]){
  			if(!visited[i]){
  				DFS(i,visited);
  			}
  		}
  	}
  	public static void setGraph(int n,int m)
  	{
  		graph=new ArrayList[n+1];
  		for(int i=0;i<=n;i++){
  			graph[i]=new ArrayList<>();
  		}
  		for(int i=0;i<m;i++){
  			int u=I(),v=I();
  			graph[u].add(v);
  			graph[v].add(u);
  		}
  	}
  	public static int BS(long a[],long x,int ii,int jj)
  	{
  		// int n=a.length;
  		int mid=0;
  		int i=ii,j=jj;
  		while(i<=j)
  		{
  			mid=(i+j)/2;
  			if(a[mid]<x){
  				i=mid+1;
  			}else if(a[mid]>x){
  				j=mid-1;
  			}else{
  				return mid;
  			}
  		}
  		return -1;
  	}
  
  	//LOWER_BOUND and UPPER_BOUND functions
  
  	public static int lower_bound(long arr[],int start, int end, long X)   //start=0,end=n-1
  	{
  		if(arr[arr.length-1]<X)return end;
  		if(arr[0]>X)return -1;
  		int left=start,right=end;
  		while(left<right){
  			int mid=(left+right)/2;
  			if(arr[mid]==X){                                      //Returns last index of lower bound value.
  				if(mid<end && arr[mid+1]==X){
  					left=mid+1;
  				}else{
  					return mid;
  				}
  			}
  			// if(arr[mid]==X){                                   //Returns first index of lower bound value.
  			// 	if(mid>start && arr[mid-1]==X){
  			// 		right=mid-1;
  			// 	}else{
  			// 		return mid;
  			// 	}
  			// }
  			else if(arr[mid]>X){
  				if(mid>start && arr[mid-1]<X){
  					return mid-1;
  				}else{
  					right=mid-1;
  				}
  			}else{
  				if(mid<end && arr[mid+1]>X){
  					return mid;
  				}else{
  					left=mid+1;
  				}
  			}
  		}
  		return left;
  	}
  	public static int upper_bound(long arr[],int start,int end,long X)			//start=0,end=n-1
  	{
  		if(arr[0]>=X)return start;
  		if(arr[arr.length-1]<X)return -1;
  		int left=start,right=end;
  		while(left<right){
  			int mid=(left+right)/2;
  			if(arr[mid]==X){                                   //returns first index of upper bound value.
  				if(mid>start && arr[mid-1]==X){
  					right=mid-1;
  				}else{
  					return mid;
  				}
  			}
  			// if(arr[mid]==X){									//returns last index of upper bound value.
  			// 	if(mid<end && arr[mid+1]==X){
  			// 		left=mid+1;
  			// 	}else{
  			// 		return mid;
  			// 	}
  			// }
  			else if(arr[mid]>X){
  				if(mid>start && arr[mid-1]<X){
  					return mid;
  				}else{
  					right=mid-1;
  				}
  			}else{
  				if(mid<end && arr[mid+1]>X){
  					return mid+1;
  				}else{
  					left=mid+1;
  				}
  			}
  		}
  		return left;
  	}
  
  	//END
  
  	public static boolean isSorted(int a[])
  	{
  		int n=a.length;
  		for(int i=0;i<n-1;i++){
  			if(a[i]>a[i+1])return false;
  		}
  		return true;
  	}
  	public static boolean isSorted(long a[])
  	{
  		int n=a.length;
  		for(int i=0;i<n-1;i++){
  			if(a[i]>a[i+1])return false;
  		}
  		return true;
  	}
  	public static int computeXOR(int n) //compute XOR of all numbers between 1 to n.
      {
          if (n % 4 == 0)
              return n;
          if (n % 4 == 1)
              return 1;
          if (n % 4 == 2)
              return n + 1;
          return 0;
      }
  	public static ArrayList<Integer> primeSieve(int n)
  	{
  	    ArrayList<Integer> arr=new ArrayList<>();
  	    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] == true)
              {
                  for (int i = p * p; i <= n; i += p)
                  prime[i] = false;
              }
          }
          for (int i = 2; i <= n; i++)
          {
              if (prime[i] == true)
              arr.add(i);
          }
          return arr;
  	}
  
  	// Fenwick / BinaryIndexed  Tree  USE IT - FenwickTree ft1=new FenwickTree(n);
  	public static class FenwickTree
  	{
  		int farr[];
  		int n;
  		public FenwickTree(int c)
  		{
  			n=c+1;
  			farr=new int[n];
  		}
  		// public void update_range(int l,int r,long p)
  		// {
  		// 	update(l,p);
  		// 	update(r+1,(-1)*p);
  		// }
  		public void update(int x,int p)
  		{
  			for(;x<n;x+=x&(-x))
  			{
  				farr[x]+=p;
  			}
  		}
  		public long get(int x)
  		{
  			long ans=0;
  			for(;x>0;x-=x&(-x))
  			{
  				ans=ans+farr[x];
  			}
  			return ans;
  		}
  	}
  	//Disjoint Set Union
  	public static class DSU
  	{
  	    int par[],rank[];
  	    public DSU(int c)
  	    {
  	        par=new int[c+1];
  	        rank=new int[c+1];
  	        for(int i=0;i<=c;i++)
  	        {
  	            par[i]=i;
  	            rank[i]=0;
  	        }
  	    }
  	    public int find(int a)
  	    {
  	        if(a==par[a])
  	        return a;
  	        return par[a]=find(par[a]);
  	    }
  	    public void union(int a,int b)
  	    {
  	        int a_rep=find(a),b_rep=find(b);
  	        if(a_rep==b_rep)
  	        return;
  	        if(rank[a_rep]<rank[b_rep])
  	        par[a_rep]=b_rep;
  	        else if(rank[a_rep]>rank[b_rep])
  	        par[b_rep]=a_rep;
  	        else
  	        {
  	            par[b_rep]=a_rep;
  	            rank[a_rep]++;
  	        }
  	    }
  	}
  	
      public static class myComp1 implements Comparator<pair1>
      {
  		//sort in ascending order.
      	public int compare(pair1 p1,pair1 p2)
      	{
      	    if(p1.a==p2.a)
      	    return 0;
      	    else if(p1.a<p2.a)
      	    return -1;
      	    else
      	    return 1;
      	}
  		//sort in descending order.
  		// public int compare(pair p1,pair p2)
      	// {
      	//     if(p1.a==p2.a)
      	//     return 0;
      	//     else if(p1.a<p2.a)
      	//     return 1;
      	//     else
      	//     return -1;
      	// }
      }
  	public static class pair1
      {
      	long a;
      	long b;
      	public pair1(long val,long index)
      	{
      	    a=val;
      	    b=index;
      	}
      }
      public static ArrayList<pair1> mergeIntervals(ArrayList<pair1> arr)
  	{
  	    //****************use this in main function-Collections.sort(arr,new myComp1());
  	    ArrayList<pair1> a1=new ArrayList<>();
  	    if(arr.size()<=1)
  	    return arr;
  	    a1.add(arr.get(0));
  	    int i=1,j=0;
  	    while(i<arr.size())
  	    {
  	        if(a1.get(j).b<arr.get(i).a)
  	        {
  	           a1.add(arr.get(i));
  	           i++;
  	           j++;
  	        }
  	        else if(a1.get(j).b>arr.get(i).a && a1.get(j).b>=arr.get(i).b)
  	        {
  	            i++;
  	        }
  	        else if(a1.get(j).b>=arr.get(i).a)
  	        {
  	            long a=a1.get(j).a;
  	            long b=arr.get(i).b;
  	            a1.remove(j);
  	            a1.add(new pair1(a,b));
  	            i++;
  	        }
  	    }
  	    return a1;
  	}
  	public static ArrayList<Long> primeFact(long a)
  	{
  	    ArrayList<Long> arr=new ArrayList<>();
  	    while(a%2==0){
  	        arr.add(2L);
  	        a=a/2;
  	    }
  	    for(long i=3;i*i<=a;i+=2){
  	        while(a%i==0){
  	            arr.add(i);
  	            a=a/i;
  	        }
  	    }
  	    if(a>2)arr.add(a);
  	    return arr;
  	}
  	public static boolean isInteger(double N)
  	{
  		int X = (int)N;
  		double temp2 = N - X;
  		if (temp2 > 0)
  		{
  			return false;
  		}
  		return true;
  	}
  	public static boolean isPalindrome(String s,int n)
  	{
  		for(int i=0;i<=n/2;i++){
  			if(s.charAt(i)!=s.charAt(n-i-1)){
  				return false;
  			}
  		}
  		return true;
  	}
  	public static int gcd(int a,int b)
  	{
  	    if(b==0)
  	    return a;
  	    else
  	    return gcd(b,a%b);
  	}
  	public static long gcd(long a,long b)
  	{
  	    if(b==0)
  	    return a;
  	    else
  	    return gcd(b,a%b);
  	}
  	public static long fact(long n)
  	{
  		long fact=1;
  		for(long i=2;i<=n;i++){
  			fact=((fact%mod)*(i%mod))%mod;
  		}
  		return fact;
  	}
  	public static long fact(int n)
  	{
  		long fact=1;
  		for(int i=2;i<=n;i++){
  			fact=((fact%mod)*(i%mod))%mod;
  		}
  		return fact;
  	} 
  	public static boolean isPrime(int n) 
  	{ 
  	    if (n <= 1) 
  	        return false; 
  	    if (n <= 3) 
  	        return true; 
  	    if (n % 2 == 0 || n % 3 == 0) 
  	        return false; 
  	    double sq=Math.sqrt(n);
  	  
  	    for (int i = 5; i <= sq; i = i + 6) 
  	        if (n % i == 0 || n % (i + 2) == 0) 
  	            return false; 
  	    return true; 
  	} 
      public static boolean isPrime(long n) 
  	{ 
  	    if (n <= 1) 
  	        return false; 
  	    if (n <= 3) 
  	        return true; 
  	    if (n % 2 == 0 || n % 3 == 0) 
  	        return false; 
  	    double sq=Math.sqrt(n);
  	
  	    for (int i = 5; i <= sq; i = i + 6) 
  	        if (n % i == 0 || n % (i + 2) == 0) 
  	            return false; 
  	    return true; 
  	}
  	public static void printArray(long a[])
  	{
  		for(int i=0;i<a.length;i++){
  			out.print(a[i]+" ");
  		}
  		out.println();
  	}
  	public static void printArray(int a[])
  	{
  		for(int i=0;i<a.length;i++){
  			out.print(a[i]+" ");
  		}
  		out.println();
  	}
  	public static void printArray(char a[])
  	{
  		for(int i=0;i<a.length;i++){
  			out.print(a[i]);
  		}
  		out.println();
  	}
  	public static void printArray(String a[])
  	{
  		for(int i=0;i<a.length;i++){
  			out.print(a[i]+" ");
  		}
  		out.println();
  	}
  	public static void printArray(boolean a[])
  	{
  		for(int i=0;i<a.length;i++){
  			out.print(a[i]+" ");
  		}
  		out.println();
  	}
  	public static void printArray(pair a[])
  	{
  		for(pair p:a){
  			out.println(p.a+"->"+p.b);
  		}
  	}
  	public static void printArray(int a[][])
  	{
  		for(int i=0;i<a.length;i++){
  			for(int j=0;j<a[i].length;j++){
  				out.print(a[i][j]+" ");
  			}out.println();
  		}
  	}
  	public static void printArray(long a[][])
  	{
  		for(int i=0;i<a.length;i++){
  			for(int j=0;j<a[i].length;j++){
  				out.print(a[i][j]+" ");
  			}out.println();
  		}
  	}
  	public static void printArray(char a[][])
  	{
  		for(int i=0;i<a.length;i++){
  			for(int j=0;j<a[i].length;j++){
  				out.print(a[i][j]+" ");
  			}out.println();
  		}
  	}
  	public static void printArrayL(ArrayList<Long> arr)
  	{
  		for(int i=0;i<arr.size();i++){
  			out.print(arr.get(i)+" ");
  		}
  		out.println();
  	}
  	public static void printArrayI(ArrayList<Integer> arr)
  	{
  		for(int i=0;i<arr.size();i++){
  			out.print(arr.get(i)+" ");
  		}
  		out.println();
  	}
  	public static void printArrayS(ArrayList<String> arr)
  	{
  		for(int i=0;i<arr.size();i++){
  			out.print(arr.get(i)+" ");
  		}
  		out.println();
  	}
  	public static void printMapInt(HashMap<Integer,Integer> hm){
  		for(Map.Entry<Integer,Integer> e:hm.entrySet()){
  			out.println(e.getKey()+"->"+e.getValue());
  		}out.println();
  	}
  	public static void printMapLong(HashMap<Long,Long> hm){
  		for(Map.Entry<Long,Long> e:hm.entrySet()){
  			out.println(e.getKey()+"->"+e.getValue());
  		}out.println();
  	}
  
  	//Modular Arithmetic
  
  	public static long add(long a,long b)
  	{
  		a+=b;
  		if(a>=mod)a-=mod;
  		return a;
  	}
  	public static long sub(long a,long b)
  	{
  		a-=b;
  		if(a<0)a+=mod;
  		return a;
  	}
  	public static long mul(long a,long b)
  	{
  		return ((a%mod)*(b%mod))%mod;
  	}
  	public static long divide(long a,long b,long m)
  	{
  		a=mul(a,modInverse(b,m));
  		return a;
  	}
  	public static long modInverse(long a,long m)
  	{
  		int x=0,y=0;
  		own p=new own(x,y);
  		long g=gcdExt(a,m,p);
  		if(g!=1){
  			out.println("inverse does not exists");
  			return -1;
  		}else{
  			long res=((p.a%m)+m)%m;
  			return res;
  		}
  	}
  	public static long gcdExt(long a,long b,own p)
  	{
  		if(b==0){
  			p.a=1;
  			p.b=0;
  			return a;
  		}
  		int x1=0,y1=0;
  		own p1=new own(x1,y1);
  		long gcd=gcdExt(b,a%b,p1);
  		p.b=p1.a - (a/b) * p1.b;
  		p.a=p1.b;
  		return gcd;
  	}
  	public static long pwr(long m,long n)
  	{
  		long res=1;
  		m=m%mod;
  		if(m==0)
  		return 0;
  		while(n>0)
  		{
  			if((n&1)!=0)
  			{
  				res=(res*m)%mod;
  			}
  			n=n>>1;
  			m=(m*m)%mod;
  		}
  		return res;
  	}
  	public static class own
      {
      	long a;
      	long b;
      	public own(long val,long index)
      	{
      	    a=val;
      	    b=index;
      	}
      }
  
  	//Modular Airthmetic
  
  	public static void sort(int[] A)
  	{
          int n = A.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i)
  		{
              int tmp = A[i];
              int randomPos = i + rnd.nextInt(n-i);
              A[i] = A[randomPos];
              A[randomPos] = tmp;
          }
          Arrays.sort(A);
      }
  	public static void sort(char[] A)
  	{
          int n = A.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i)
  		{
              char tmp = A[i];
              int randomPos = i + rnd.nextInt(n-i);
              A[i] = A[randomPos];
              A[randomPos] = tmp;
          }
          Arrays.sort(A);
      }
      public static void sort(long[] A)
  	{
  	    int n = A.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i)
  		{
              long tmp = A[i];
              int randomPos = i + rnd.nextInt(n-i);
              A[i] = A[randomPos];
              A[randomPos] = tmp;
          }
  	    Arrays.sort(A);
  	}
  	public static int I(){return sc.I();}
      public static long L(){return sc.L();}
      public static String S(){return sc.S();}
      public static double D(){return sc.D();}
  }
  class FastReader {  
      BufferedReader br;
      StringTokenizer st;
      public FastReader(){
          br = new BufferedReader(new InputStreamReader(System.in));
      }
      String next(){
          while (st == null || !st.hasMoreElements()){
              try {
                  st = new StringTokenizer(br.readLine());
              }
              catch (IOException e){
                  e.printStackTrace();
              }
          }
          return st.nextToken();
      }
      int I(){ 
          return Integer.parseInt(next());
      }
      long L(){ 
          return Long.parseLong(next());
      }
      double D(){
           return Double.parseDouble(next());
      }
      String S(){
          String str = "";
          try 
          {
              str = br.readLine();
          }
          catch (IOException e)
          {
              e.printStackTrace();
          }
          return str;
      }
  }
  