Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
vector<string> rowFirst(int n, int m, vector<vector<int>> g) {
  vector<string> moves;
  for (int(i) = (0); (i) < (n); ++(i)) {
    int mn = 1000000;
    for (int(j) = (0); (j) < (m); ++(j)) {
      if (g[i][j] < mn) mn = g[i][j];
    }
    for (int(j) = (0); (j) < (m); ++(j)) {
      g[i][j] -= mn;
    }
    for (int(j) = (0); (j) < (mn); ++(j))
      moves.push_back("row " + to_string(i + 1));
  }
  for (int(i) = (0); (i) < (m); ++(i)) {
    int mn = 1000000;
    for (int(j) = (0); (j) < (n); ++(j)) {
      if (g[j][i] < mn) mn = g[j][i];
    }
    for (int(j) = (0); (j) < (n); ++(j)) {
      g[j][i] -= mn;
    }
    for (int(j) = (0); (j) < (mn); ++(j))
      moves.push_back("col " + to_string(i + 1));
  }
  bool empty = true;
  for (int(i) = (0); (i) < (n); ++(i))
    for (int(j) = (0); (j) < (m); ++(j))
      if (g[i][j]) empty = false;
  if (!empty) {
    moves.clear();
    moves.push_back("-1");
  }
  return moves;
}
vector<string> colFirst(int n, int m, vector<vector<int>> g) {
  vector<string> moves;
  for (int(i) = (0); (i) < (m); ++(i)) {
    int mn = 1000000;
    for (int(j) = (0); (j) < (n); ++(j)) {
      if (g[j][i] < mn) mn = g[j][i];
    }
    for (int(j) = (0); (j) < (n); ++(j)) {
      g[j][i] -= mn;
    }
    for (int(j) = (0); (j) < (mn); ++(j))
      moves.push_back("col " + to_string(i + 1));
  }
  for (int(i) = (0); (i) < (n); ++(i)) {
    int mn = 1000000;
    for (int(j) = (0); (j) < (m); ++(j)) {
      if (g[i][j] < mn) mn = g[i][j];
    }
    for (int(j) = (0); (j) < (m); ++(j)) {
      g[i][j] -= mn;
    }
    for (int(j) = (0); (j) < (mn); ++(j))
      moves.push_back("row " + to_string(i + 1));
  }
  bool empty = true;
  for (int(i) = (0); (i) < (n); ++(i))
    for (int(j) = (0); (j) < (m); ++(j))
      if (g[i][j]) empty = false;
  if (!empty) {
    moves.clear();
    moves.push_back("-1");
  }
  return moves;
}
int main() {
  int n, m;
  cin >> n >> m;
  vector<vector<int>> g(n, vector<int>(m, 0));
  for (int(i) = (0); (i) < (n); ++(i))
    for (int(j) = (0); (j) < (m); ++(j)) cin >> g[i][j];
  vector<string> rf, cf;
  rf = rowFirst(n, m, g);
  cf = colFirst(n, m, g);
  if (rf.size() && rf[0] == "-1") return puts("-1");
  if (rf.size() < cf.size()) {
    cout << rf.size() << endl;
    for (int(i) = (0); (i) < (rf.size()); ++(i)) cout << rf[i] << endl;
  } else {
    cout << cf.size() << endl;
    for (int(i) = (0); (i) < (cf.size()); ++(i)) cout << cf[i] << endl;
  }
  return 0;
}