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.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.io.FilterInputStream;
import java.io.BufferedInputStream;
import java.util.ArrayList;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author khokharnikunj8
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        ScanReader in = new ScanReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C816 solver = new C816();
        solver.solve(1, in, out);
        out.close();
    }

    static class C816 {
        public void solve(int testNumber, ScanReader in, PrintWriter out) {
            int n = in.scanInt();
            int m = in.scanInt();
            int minRow[] = new int[n];
            int minColumn[] = new int[m];
            Arrays.fill(minRow, Integer.MAX_VALUE);
            Arrays.fill(minColumn, Integer.MAX_VALUE);
            int array[][] = new int[n][m];
            int array1[][] = new int[n][m];
            boolean flag = true;
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    array1[i][j] = array[i][j] = in.scanInt();
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    minRow[i] = Math.min(minRow[i], array[i][j]);
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    array[i][j] -= minRow[i];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    minColumn[j] = Math.min(minColumn[j], array[i][j]);
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    array[i][j] -= minColumn[j];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    if (array[i][j] != 0) flag = false;
            if (!flag) {
                out.println(-1);
                return;
            }
            ArrayList<String> ans = new ArrayList<>();
            for (int i = 0; i < n; i++)
                if (minRow[i] != 0)
                    for (int j = 0; j < minRow[i]; j++)
                        ans.add("row " + (i + 1));
            for (int i = 0; i < m; i++)
                if (minColumn[i] != 0)
                    for (int j = 0; j < minColumn[i]; j++)
                        ans.add("col " + (i + 1));

            Arrays.fill(minRow, Integer.MAX_VALUE);
            Arrays.fill(minColumn, Integer.MAX_VALUE);
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    minColumn[j] = Math.min(minColumn[j], array1[i][j]);
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    array1[i][j] -= minColumn[j];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    minRow[i] = Math.min(minRow[i], array1[i][j]);
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    array1[i][j] -= minRow[i];

            ArrayList<String> ans1 = new ArrayList<>();
            for (int i = 0; i < n; i++)
                if (minRow[i] != 0)
                    for (int j = 0; j < minRow[i]; j++)
                        ans1.add("row " + (i + 1));
            for (int i = 0; i < m; i++)
                if (minColumn[i] != 0)
                    for (int j = 0; j < minColumn[i]; j++)
                        ans1.add("col " + (i + 1));
            if (ans.size() < ans1.size()) {
                out.println(ans.size());
                for (int i = 0; i < ans.size(); i++) out.println(ans.get(i));
            } else {
                out.println(ans1.size());
                for (int i = 0; i < ans1.size(); i++) out.println(ans1.get(i));
            }

        }

    }

    static class ScanReader {
        private byte[] buf = new byte[4 * 1024];
        private int index;
        private BufferedInputStream in;
        private int total;

        public ScanReader(InputStream inputStream) {
            in = new BufferedInputStream(inputStream);
        }

        private int scan() {
            if (index >= total) {
                index = 0;
                try {
                    total = in.read(buf);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                if (total <= 0) return -1;
            }
            return buf[index++];
        }

        public int scanInt() {
            int integer = 0;
            int n = scan();
            while (isWhiteSpace(n)) n = scan();
            int neg = 1;
            if (n == '-') {
                neg = -1;
                n = scan();
            }
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    integer *= 10;
                    integer += n - '0';
                    n = scan();
                }
            }
            return neg * integer;
        }

        private boolean isWhiteSpace(int n) {
            if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1) return true;
            else return false;
        }

    }
}