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.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

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

    static class CKarenAndGame {
        public void solve(int testNumber, InputReader c, OutputWriter w) {

            int n = c.readInt(), m = c.readInt();
            int mat[][] = new int[n][];
            for (int i = 0; i < n; i++) {
                mat[i] = c.readIntArray(m);
            }

            int rows[] = new int[n];
            int col[] = new int[m];
            if (n < m) {

                for (int i = 0; i < n; i++) {
                    int min = mat[i][0];
                    for (int j = 0; j < m; j++) {
                        min = Math.min(min, mat[i][j]);
                    }
                    rows[i] = min;
                    for (int j = 0; j < m; j++) {
                        mat[i][j] -= min;
                    }
                }

                for (int i = 0; i < m; i++) {
                    int min = mat[0][i];
                    for (int j = 0; j < n; j++) {
                        min = Math.min(min, mat[j][i]);
                    }
                    col[i] = min;
                    for (int j = 0; j < n; j++) {
                        mat[j][i] -= min;
                    }
                }
            } else {
                for (int i = 0; i < m; i++) {
                    int min = mat[0][i];
                    for (int j = 0; j < n; j++) {
                        min = Math.min(min, mat[j][i]);
                    }
                    col[i] = min;
                    for (int j = 0; j < n; j++) {
                        mat[j][i] -= min;
                    }
                }

                for (int i = 0; i < n; i++) {
                    int min = mat[i][0];
                    for (int j = 0; j < m; j++) {
                        min = Math.min(min, mat[i][j]);
                    }
                    rows[i] = min;
                    for (int j = 0; j < m; j++) {
                        mat[i][j] -= min;
                    }
                }
            }
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    if (mat[i][j] != 0) {
                        w.printLine(-1);
                        return;
                    }
                }
            }

            int res = 0;
            for (int i = 0; i < n; i++) {
                res += rows[i];
            }
            for (int j = 0; j < m; j++) {
                res += col[j];
            }


            w.printLine(res);
            for (int i = 0; i < n; i++) {
                while (rows[i] != 0) {
                    w.printLine("row " + (i + 1));
                    rows[i]--;
                }
            }


            for (int j = 0; j < m; j++) {
                while (col[j] != 0) {
                    w.printLine("col " + (j + 1));
                    col[j]--;
                }
            }
        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int[] readIntArray(int size) {
            int[] array = new int[size];
            for (int i = 0; i < size; i++) {
                array[i] = readInt();
            }
            return array;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int readInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }

    static class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }

        public void print(Object... objects) {
            for (int i = 0; i < objects.length; i++) {
                if (i != 0) {
                    writer.print(' ');
                }
                writer.print(objects[i]);
            }
        }

        public void printLine(Object... objects) {
            print(objects);
            writer.println();
        }

        public void close() {
            writer.close();
        }

        public void printLine(int i) {
            writer.println(i);
        }

    }
}