description: You are given a matrix, consisting of n rows and m columns. The j-th cell of the i-th row contains an integer a_{ij}.
  
  First, you have to color each row of the matrix either red or blue in such a way that at least one row is colored red and at least one row is colored blue.
  
  Then, you have to choose an integer k (1 ≤ k < m) and cut the colored matrix in such a way that the first k columns become a separate matrix (the left matrix) and the last m-k columns become a separate matrix (the right matrix).
  
  The coloring and the cut are called perfect if two properties hold: 
  
    * every red cell in the left matrix contains an integer greater than every blue cell in the left matrix; 
    * every blue cell in the right matrix contains an integer greater than every red cell in the right matrix. 
  
  
  
  Find any perfect coloring and cut, or report that there are none.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of testcases.
  
  Then the descriptions of t testcases follow.
  
  The first line of each testcase contains two integers n and m (2 ≤ n, m ≤ 5 ⋅ 10^5; n ⋅ m ≤ 10^6) — the number of rows and the number of columns in the matrix, respectively.
  
  The i-th of the next n lines contains m integers a_{i1}, a_{i2}, ..., a_{im} (1 ≤ a_{ij} ≤ 10^6).
  
  The sum of n ⋅ m over all testcases doesn't exceed 10^6.
  
  Output
  
  For each testcase print an answer. If there are no perfect colorings and cuts in the matrix, then print "NO".
  
  Otherwise, first, print "YES". Then a string, consisting of n characters: the i-th character should be 'R' if the i-th row is colored red and 'B' if it's colored blue. The string should contain at least one 'R' and at least one 'B'. Finally, print an integer k (1 ≤ k < m) — the number of columns from the left that are cut.
  
  Example
  
  Input
  
  
  3
  5 5
  1 5 8 8 7
  5 2 1 4 3
  1 6 9 7 5
  9 3 3 3 2
  1 7 9 9 8
  3 3
  8 9 8
  1 5 3
  7 5 7
  2 6
  3 3 3 2 2 2
  1 1 1 4 4 4
  
  
  Output
  
  
  YES
  BRBRB 1
  NO
  YES
  RB 3
  
  Note
  
  The coloring and the cut for the first testcase:
  
  <image>
solution: 
  import java.io.*;
  import java.util.*;
  
  public final class Main {
  
      static PrintWriter out = new PrintWriter(System.out);
      static FastReader in = new FastReader();
      static Pair[] moves = new Pair[]{new Pair(-1, 0), new Pair(0, 1), new Pair(1, 0), new Pair(0, -1)};
      static int mod = (int) (1e9 + 7);
      static int mod2 = 998244353;
  
      public static void main(String[] args) {
          int tt = i();
          while (tt-- > 0) {
              solve();
          }
          out.flush();
      }
  
      public static void solve() {
          int n = i();
          int m = i();
          int[][] mat = new int[n][m + 1];
          for (int i = 0; i < n; i++) {
              for (int j = 0; j < m; j++) {
                  mat[i][j] = i();
              }
              mat[i][m] = i;
          }
          Arrays.sort(mat, new Comparator<int[]>() {
              @Override
              public int compare(int[] o1, int[] o2) {
                  return o1[0] - o2[0];
              }
          });
  
          int[][] x1 = new int[n][m];
          int[][] x2 = new int[n][m];
          int[][] x3 = new int[n][m];
          int[][] x4 = new int[n][m];
  
          for (int i = 0; i < n; i++) {
              for (int j = 0; j < m; j++) {
                  x1[i][j] = mat[i][j];
                  x1[i][j] = Math.max(x1[i][j], (i - 1 >= 0) ? x1[i - 1][j] : 0);
                  x1[i][j] = Math.max(x1[i][j], (j - 1 >= 0) ? x1[i][j - 1] : 0);
              }
          }
  
          for (int i = 0; i < n; i++) {
              for (int j = m - 1; j >= 0; j--) {
                  x2[i][j] = mat[i][j];
                  x2[i][j] = Math.min(x2[i][j], (i - 1 >= 0) ? x2[i - 1][j] : Integer.MAX_VALUE);
                  x2[i][j] = Math.min(x2[i][j], (j + 1 < m) ? x2[i][j + 1] : Integer.MAX_VALUE);
              }
          }
  
          for (int i = n - 1; i >= 0; i--) {
              for (int j = 0; j < m; j++) {
                  x3[i][j] = mat[i][j];
                  x3[i][j] = Math.min(x3[i][j], (i + 1 < n) ? x3[i + 1][j] : Integer.MAX_VALUE);
                  x3[i][j] = Math.min(x3[i][j], (j - 1 >= 0) ? x3[i][j - 1] : Integer.MAX_VALUE);
              }
          }
  
          for (int i = n - 1; i >= 0; i--) {
              for (int j = m - 1; j >= 0; j--) {
                  x4[i][j] = mat[i][j];
                  x4[i][j] = Math.max(x4[i][j], (i + 1 < n) ? x4[i + 1][j] : 0);
                  x4[i][j] = Math.max(x4[i][j], (j + 1 < m) ? x4[i][j + 1] : 0);
              }
          }
  
          char[] chars = new char[n];
          Arrays.fill(chars, 'R');
          for (int i = 0; i < n - 1; i++) {
              chars[mat[i][m]] = 'B';
              for (int j = 0; j < m - 1; j++) {
                  int ans1 = x1[i][j];
                  int ans2 = x2[i][j + 1];
                  int ans3 = x3[i + 1][j];
                  int ans4 = x4[i + 1][j + 1];
                  if (ans3 > ans1 && ans2 > ans4) {
                      out.println("YES");
                      out.println(new String(chars) + " " + (j + 1));
                      return;
                  }
              }
          }
          out.println("NO");
      }
  
      static long[] pre(int[] a) {
          long[] pre = new long[a.length + 1];
          pre[0] = 0;
          for (int i = 0; i < a.length; i++) {
              pre[i + 1] = pre[i] + a[i];
          }
          return pre;
      }
  
      static void print(char A[]) {
          for (char c : A) {
              out.print(c);
          }
          out.println();
      }
  
      static void print(boolean A[]) {
          for (boolean c : A) {
              out.print(c + " ");
          }
          out.println();
      }
  
      static void print(int A[]) {
          for (int c : A) {
              out.print(c + " ");
          }
          out.println();
      }
  
      static void print(long A[]) {
          for (long i : A) {
              out.print(i + " ");
          }
          out.println();
      }
  
      static void print(List<Integer> A) {
          for (int a : A) {
              out.print(a + " ");
          }
      }
  
      static int i() {
          return in.nextInt();
      }
  
      static long l() {
          return in.nextLong();
      }
  
      static double d() {
          return in.nextDouble();
      }
  
      static String s() {
          return in.nextLine();
      }
  
      static int[][] inputWithIdx(int N) {
          int A[][] = new int[N][2];
          for (int i = 0; i < N; i++) {
              A[i] = new int[]{i, in.nextInt()};
          }
          return A;
      }
  
      static int[] input(int N) {
          int A[] = new int[N];
          for (int i = 0; i < N; i++) {
              A[i] = in.nextInt();
          }
          return A;
      }
  
      static long[] inputLong(int N) {
          long A[] = new long[N];
          for (int i = 0; i < A.length; i++) {
              A[i] = in.nextLong();
          }
          return A;
      }
  
      static int GCD(int a, int b) {
          if (b == 0) {
              return a;
          } else {
              return GCD(b, a % b);
          }
      }
  
      static long GCD(long a, long b) {
          if (b == 0) {
              return a;
          } else {
              return GCD(b, a % b);
          }
      }
  
      static long LCM(int a, int b) {
          return (long) a / GCD(a, b) * b;
      }
  
      static long LCM(long a, long b) {
          return a / GCD(a, b) * b;
      }
  
      static void shuffleAndSort(int[] arr) {
          for (int i = 0; i < arr.length; i++) {
              int rand = (int) (Math.random() * arr.length);
              int temp = arr[rand];
              arr[rand] = arr[i];
              arr[i] = temp;
          }
          Arrays.sort(arr);
      }
  
      static void shuffleAndSort(int[][] arr, Comparator<? super int[]> comparator) {
          for (int i = 0; i < arr.length; i++) {
              int rand = (int) (Math.random() * arr.length);
              int[] temp = arr[rand];
              arr[rand] = arr[i];
              arr[i] = temp;
          }
          Arrays.sort(arr, comparator);
      }
  
      static void shuffleAndSort(long[] arr) {
          for (int i = 0; i < arr.length; i++) {
              int rand = (int) (Math.random() * arr.length);
              long temp = arr[rand];
              arr[rand] = arr[i];
              arr[i] = temp;
          }
          Arrays.sort(arr);
      }
  
      static boolean isPerfectSquare(double number) {
          double sqrt = Math.sqrt(number);
          return ((sqrt - Math.floor(sqrt)) == 0);
      }
  
      static void swap(int A[], int a, int b) {
          int t = A[a];
          A[a] = A[b];
          A[b] = t;
      }
  
      static long pow(long a, long b, int mod) {
          long pow = 1;
          long x = a;
          while (b != 0) {
              if ((b & 1) != 0) {
                  pow = (pow * x) % mod;
              }
              x = (x * x) % mod;
              b /= 2;
          }
          return pow;
      }
  
      static long pow(long a, long b) {
          long pow = 1;
          long x = a;
          while (b != 0) {
              if ((b & 1) != 0) {
                  pow *= x;
              }
              x = x * x;
              b /= 2;
          }
          return pow;
      }
  
      static long modInverse(long x, int mod) {
          return pow(x, mod - 2, mod);
      }
  
      static boolean isPrime(long N) {
          if (N <= 1) {
              return false;
          }
          if (N <= 3) {
              return true;
          }
          if (N % 2 == 0 || N % 3 == 0) {
              return false;
          }
          for (int i = 5; i * i <= N; i = i + 6) {
              if (N % i == 0 || N % (i + 2) == 0) {
                  return false;
              }
          }
          return true;
      }
  
      public static String reverse(String str) {
          if (str == null) {
              return null;
          }
          return new StringBuilder(str).reverse().toString();
      }
  
      public static String repeat(char ch, int repeat) {
          if (repeat <= 0) {
              return "";
          }
          final char[] buf = new char[repeat];
          for (int i = repeat - 1; i >= 0; i--) {
              buf[i] = ch;
          }
          return new String(buf);
      }
  
      public static int[] manacher(String s) {
          char[] chars = s.toCharArray();
          int n = s.length();
          int[] d1 = new int[n];
          for (int i = 0, l = 0, r = -1; i < n; i++) {
              int k = (i > r) ? 1 : Math.min(d1[l + r - i], r - i + 1);
              while (0 <= i - k && i + k < n && chars[i - k] == chars[i + k]) {
                  k++;
              }
              d1[i] = k--;
              if (i + k > r) {
                  l = i - k;
                  r = i + k;
              }
          }
          return d1;
      }
  
      public static int[] kmp(String s) {
          int n = s.length();
          int[] res = new int[n];
          for (int i = 1; i < n; ++i) {
              int j = res[i - 1];
              while (j > 0 && s.charAt(i) != s.charAt(j)) {
                  j = res[j - 1];
              }
              if (s.charAt(i) == s.charAt(j)) {
                  ++j;
              }
              res[i] = j;
          }
          return res;
      }
  }
  
  class Pair {
  
      int i, j;
  
      Pair(int i, int j) {
          this.i = i;
          this.j = j;
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) {
              return true;
          }
          if (o == null || getClass() != o.getClass()) {
              return false;
          }
          Pair pair = (Pair) o;
          return i == pair.i && j == pair.j;
      }
  
      @Override
      public int hashCode() {
          return Objects.hash(i, j);
      }
  }
  
  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 nextInt() {
          return Integer.parseInt(next());
      }
  
      long nextLong() {
          return Long.parseLong(next());
      }
  
      double nextDouble() {
          return Double.parseDouble(next());
      }
  
      String nextLine() {
          String str = "";
          try {
              str = br.readLine();
          } catch (IOException e) {
              e.printStackTrace();
          }
          return str;
      }
  }
  
  class Node {
  
      int data, open, close;
  
      Node() {
          this(0, 0, 0);
      }
  
      Node(int data, int open, int close) {
          this.data = data;
          this.open = open;
          this.close = close;
      }
  }
  
  class ST {
  
      int n;
      Node[] st;
  
      ST(int n) {
          this.n = n;
          st = new Node[4 * Integer.highestOneBit(n)];
      }
  
      void build(Node[] nodes) {
          build(0, 0, n - 1, nodes);
      }
  
      private void build(int id, int l, int r, Node[] nodes) {
          if (l == r) {
              st[id] = nodes[l];
              return;
          }
          int mid = (l + r) >> 1;
          build((id << 1) + 1, l, mid, nodes);
          build((id << 1) + 2, mid + 1, r, nodes);
          st[id] = comb(st[(id << 1) + 1], st[(id << 1) + 2]);
      }
  
      void update(int i, Node node) {
          update(0, 0, n - 1, i, node);
      }
  
      private void update(int id, int l, int r, int i, Node node) {
          if (i < l || r < i) {
              return;
          }
          if (l == r) {
              st[id] = node;
              return;
          }
          int mid = (l + r) >> 1;
          update((id << 1) + 1, l, mid, i, node);
          update((id << 1) + 2, mid + 1, r, i, node);
          st[id] = comb(st[(id << 1) + 1], st[(id << 1) + 2]);
      }
  
      Node get(int x, int y) {
          return get(0, 0, n - 1, x, y);
      }
  
      private Node get(int id, int l, int r, int x, int y) {
          if (x > r || y < l) {
              return new Node();
          }
          if (x <= l && r <= y) {
              return st[id];
          }
          int mid = (l + r) >> 1;
          return comb(get((id << 1) + 1, l, mid, x, y), get((id << 1) + 2, mid + 1, r, x, y));
      }
  
      Node comb(Node a, Node b) {
          if (a == null) {
              return b;
          }
          if (b == null) {
              return a;
          }
          int min = Math.min(a.open, b.close);
          return new Node(a.data + b.data + min * 2, a.open + b.open - min, a.close + b.close - min);
      }
  }