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:

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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 JAVA):

Solution:
import java.util.ArrayList;
import java.util.Scanner;

/**
 * Created by Altynbek on 17.06.2017.
 */
public class CR419D2C {

    ArrayList<String> ans = new ArrayList<>();

    public void removeRow(int n, int m, int[][] f) {
        for (int i = 0; i < n; i++) {
            int min = 501;
            for (int j = 0; j < m; j++) {
                min = Math.min(min, f[i][j]);
            }
            if (min > 0) {
                for (int k = 0; k < min; k++) {
                    ans.add("row " + (i + 1));
                }
                for (int j = 0; j < m; j++) {
                    f[i][j] -= min;
                }
            }
        }
    }

    public void removeCol(int n, int m, int[][] f) {
        for (int j = 0; j < m; j++) {
            int min = 501;
            for (int i = 0; i < n; i++) {
                min = Math.min(min, f[i][j]);
            }
            if (min > 0) {
                for (int k = 0; k < min; k++) {
                    ans.add("col " + (j + 1));
                }
                for (int i = 0; i < n; i++) {
                    f[i][j] -= min;
                }
            }
        }
    }

    public void solve() {
        Scanner in = new Scanner(System.in);

        int n = in.nextInt();
        int m = in.nextInt();
        int[][] f = new int[n][m];
        for  (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                f[i][j] = in.nextInt();
            }
        }

        if (n <= m) {
            removeRow(n, m, f);
            removeCol(n, m, f);
        } else {
            removeCol(n, m, f);
            removeRow(n, m, f);
        }

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (f[i][j] > 0) {
                    System.out.println(-1);
                    return;
                }
            }
        }
        System.out.println(ans.size());
        for (int k = 0; k < ans.size(); k++) {
            System.out.println(ans.get(k));
        }
    }

    public static void main(String args[]) {
        new CR419D2C().solve();
    }
}