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:

<image>

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.*;
import java.math.*;
import java.util.concurrent.*;

public final class round_419_c
{
    static BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
	static FastScanner sc=new FastScanner(br);
    static PrintWriter out=new PrintWriter(System.out);
	static Random rnd=new Random();
	static String[] arr=new String[]{"row","col"};
	static int[][] val;
	static int n,m;
	static List<Pair> fl=new ArrayList<Pair>();
	
	static List<Pair> solve1()
	{
		int[] min=new int[m];Arrays.fill(min,Integer.MAX_VALUE);
		
		int[][] a=new int[n][m];
		
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<m;j++)
			{
				a[i][j]=val[i][j];
			}
		}
		
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<m;j++)
			{
				min[j]=Math.min(min[j],a[i][j]);
			}
		}
		
		List<Pair> list=new ArrayList<Pair>();
		
		for(int i=0;i<n;i++)
		{
			int max=-1;
			
			for(int j=0;j<m;j++)
			{
				max=Math.max(max,a[i][j]-min[j]);
			}
			
			if(max>0)
			{
				for(int j=0;j<m;j++)
				{
					a[i][j]-=max;
				}
				
				for(int j=0;j<max;j++)
				{
					list.add(new Pair(0,i));
				}
			}
		}
		
		boolean ans=true;
		
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<m;j++)
			{
				if(a[i][j]<0)
				{
					ans=false;
				}
				
				if(i>0 && a[i][j]!=a[i-1][j])
				{
					ans=false;
				}
			}
		}
		
		if(ans)
		{
			for(int j=0;j<m;j++)
			{
				if(a[0][j]>0)
				{
					for(int i=0;i<a[0][j];i++)
					{
						list.add(new Pair(1,j));
					}
				}
			}
			
			return list;
		}
		
		else
		{
			return null;
		}
	}
	
	static List<Pair> solve2()
	{
		int[] min=new int[n];Arrays.fill(min,Integer.MAX_VALUE);
		
		int[][] a=new int[n][m];
		
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<m;j++)
			{
				a[i][j]=val[i][j];
			}
		}
		
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<m;j++)
			{
				min[i]=Math.min(min[i],a[i][j]);
			}
		}
		
		List<Pair> list=new ArrayList<Pair>();
		
		for(int j=0;j<m;j++)
		{
			int max=-1;
			
			for(int i=0;i<n;i++)
			{
				max=Math.max(max,a[i][j]-min[i]);
			}
			
			if(max>0)
			{
				for(int i=0;i<n;i++)
				{
					a[i][j]-=max;
				}
				
				for(int i=0;i<max;i++)
				{
					list.add(new Pair(1,j));
				}
			}
		}
		
		boolean ans=true;
		
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<m;j++)
			{
				if(a[i][j]<0)
				{
					ans=false;
				}
				
				if(j>0 && a[i][j]!=a[i][j-1])
				{
					ans=false;
				}
			}
		}
		
		if(ans)
		{
			for(int i=0;i<n;i++)
			{
				if(a[i][0]>0)
				{
					for(int j=0;j<a[i][0];j++)
					{
						list.add(new Pair(0,i));
					}
				}
			}
			
			return list;
		}
		
		else
		{
			return null;
		}
	}
	
    public static void main(String args[]) throws Exception
    {
		n=sc.nextInt();m=sc.nextInt();val=new int[n][m];int min=Integer.MAX_VALUE;
		
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<m;j++)
			{
				val[i][j]=sc.nextInt();
			}
		}
		
		List<Pair> list1=solve1(),list2=solve2();
		
		if(list1!=null)
		{
			min=list1.size();fl=list1;
		}
		
		if(list2!=null && list2.size()<min)
		{
			min=list2.size();fl=list2;
		}
		
		if(min<Integer.MAX_VALUE)
		{
			out.println(min);
			
			for(Pair z:fl)
			{
				out.println(arr[z.x]+" "+(z.y+1));
			}
		}
		
		else
		{
			out.println(-1);
		}
		
		out.close();
    }
}

class Pair
{
	int x,y;
	
	public Pair(int x,int y)
	{
		this.x=x;this.y=y;
	}
}

class FastScanner
{
    BufferedReader in;
    StringTokenizer st;

    public FastScanner(BufferedReader in) {
        this.in = in;
    }
	
    public String nextToken() throws Exception {
        while (st == null || !st.hasMoreTokens()) {
            st = new StringTokenizer(in.readLine());
        }
        return st.nextToken();
    }
	
	public String next() throws Exception {
		return nextToken().toString();
	}
	
    public int nextInt() throws Exception {
        return Integer.parseInt(nextToken());
    }

    public long nextLong() throws Exception {
        return Long.parseLong(nextToken());
    }

    public double nextDouble() throws Exception {
        return Double.parseDouble(nextToken());
    }
}