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.*;
import java.util.*;


public class KarenAndGame {

    static boolean isCompleted(int[][] a){
        int col = a[0].length;

        for (int[] ints : a) {
            for (int j = 0; j < col; j++) {
                if (ints[j] != 0) {
                    return false;
                }
            }
        }
        return true;
    }


    static boolean remCol(List<String> ans, int[][] a, int rx, int ry, boolean rev){
        if(a[rx][ry] == 0) return true;
        for (int i = 0; i < a.length; i++) {
            if(a[i][ry] <=  0){
                return false;
            }
        }
        for (int i = 0; i < a.length; i++) {
            a[i][ry] -= 1;
        }
        if (rev){
            ans.add("row " + (ry + 1));
        }
        else {
            ans.add("col " + (ry + 1));
        }
        return true;
    }

    static boolean remRow(List<String> ans, int[][] a, int rx, int ry, boolean rev){
        if(a[rx][ry] == 0) return true;
        for (int i = 0; i < a[0].length; i++) {
            if(a[rx][i] <=  0){
                return false;
            }
        }
        for (int i = 0; i < a[0].length; i++) {
            a[rx][i] -= 1;
        }
        if (rev){
            ans.add("col " + (rx + 1));
        }
        else {
            ans.add("row " + (rx + 1));
        }
        return true;
    }

    static void findAns(List<String> ans, int[][] a, boolean rev){
        if (isCompleted(a)){
            return;
        }
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < a[0].length; j++) {
                if(a[i][j] !=0){
                    if(!remRow(ans,a,i,j,rev) && !remCol(ans,a,i,j,rev)){
                        System.out.println(-1);
                        System.exit(0);
                    }
                }
            }
        }
        findAns(ans, a, rev);
    }

    public static void main(String[] args) {
        Reader s = new Reader();
        int row = s.nextInt();
        int col = s.nextInt();
        int[][] a;
        boolean rev = false;
        if(row > col){
            a = new int[col][row];
            for (int i = 0; i < row; i++) {
                for (int j = 0; j < col; j++) {
                    a[j][i] = s.nextInt();
                }
            }
            rev = true;
        }
        else {
            a = new int[row][col];
            for (int i = 0; i < row; i++) {
                for (int j = 0; j < col; j++) {
                    a[i][j] = s.nextInt();
                }
            }
        }
        List<String> ans = new ArrayList<>();
        findAns(ans,a,rev);
        System.out.println(ans.size());
        for (int i = ans.size() - 1; i>=0 ; i--) {
            System.out.println(ans.get(i));
        }

    }

    static class Reader {

        private InputStream mIs;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public Reader() {
            this(System.in);
        }

        public Reader(InputStream is) {
            mIs = is;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();

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

        public String nextLine() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndOfLine(c));
            return res.toString();
        }

        public String next() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long 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 int nextInt() {
            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) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public boolean isEndOfLine(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }

    }

}