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.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;


public class c {

	public static void main(String[] args) throws Exception{
		FastScanner in = new FastScanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		int n = in.nextInt();
		int m = in.nextInt();
		int[][] g = new int[n][m];
		for (int i = 0; i < g.length; i++) {
			for (int j = 0; j < g[i].length; j++) {
				g[i][j] = in.nextInt();
			}
		}
		int[] rows = new int[n];
		int[] cols = new int[m];
		Arrays.fill(rows, 501);
		Arrays.fill(cols, 501);
		for (int i = 0; i < g.length; i++) {
			for (int j = 0; j < g[i].length; j++) {
				if(g[i][j] <rows[i])rows[i] = g[i][j];
				if(g[i][j] <cols[j])cols[j] = g[i][j];
				if(g[i][j]>rows[i] + cols[j]){
					System.out.println("-1");
					return;
				}
			}
		}
		ArrayList<String> sol = new ArrayList<>();
		while(true){
			for (int i = 0; i < rows.length; i++) {
				for (int j = 0; j < cols.length; j++) {
					if(rows[i]>cols[j]){
						for (int w = 0; w < rows[i]-cols[j]; w++) {
								sol.add("row " + (i+1));
						}
						for (int k = 0; k < cols.length; k++) {
							g[i][k]-=(rows[i] - cols[j]);
							if(g[i][k]<cols[k])cols[k] = g[i][k];
						}
						rows[i] = cols[j];
//						for (int[] is : g){
//							System.out.println(Arrays.toString(is));
//						}
//						System.out.println();
					} else if(cols[j]>rows[i]){
						for (int w = 0; w < cols[j]-rows[i]; w++) {
							sol.add("col " + (j+1));
						}
						for (int k = 0; k < rows.length; k++) {
							g[k][j]-=(cols[j] - rows[i]);
							if(g[k][j]<rows[k])rows[k] = g[k][j];
						}
						cols[j] = rows[i];
//						for (int[] is : g){
//							System.out.println(Arrays.toString(is));
//						}
//						System.out.println();
					}
				}
			}
			boolean done = true;
			for (int i = 0; i < rows.length; i++) {
				for (int j = 0; j < cols.length; j++) {
					if(rows[i] != cols[j]){
						done = false;
					}
				}
			}
			if(done)break;
		}
		for (int i = 0; i < rows.length; i++) {
			for (int j = 0; j < cols.length; j++) {
				if(g[i][j] > rows[i]){
					System.out.println("-1");
					return;
				}
			}
		}
		if(n>m){
			for (int i = 0; i < cols.length; i++) {
				for (int j = 0; j < cols[i]; j++) {
					sol.add("col " + (i+1));
				}
			}
		} else {
			for (int i = 0; i < rows.length; i++) {
				for (int j = 0; j < rows[i]; j++) {
					sol.add("row " + (i+1));
				}
			}
		}
		out.println(sol.size());
		for (String s : sol) {
			out.println(s);
		}
		out.close();
	}
	static class FastScanner {
		BufferedReader br;
		StringTokenizer st;

		public FastScanner(InputStream in) {
			br = new BufferedReader(new InputStreamReader(in));
			st = new StringTokenizer("");
		}

		public String next() throws IOException {
			while (!st.hasMoreElements())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws NumberFormatException, IOException {
			return Integer.parseInt(next());
		}
	}
}