/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{Scanner sc=new Scanner(System.in);int sugg=0;
	int n=sc.nextInt();int[][] f=new int[n][n];sc.nextLine();
	for(int i=0;i<n;i++)
	{String s=sc.nextLine();
		for(int j=0;j<n;j++)
	{	if(i!=j)
	f[i][j]=Character.getNumericValue(s.charAt(j));
		else
		f[i][j]=0;
	}}
	for(int i=0;i<n;i++)
	{int c=0;
		for(int j=0;j<n;j++)
		{if(f[j][i]==0)
		 c++;
		}if(c<n)
		sugg=c-1+sugg;
	}System.out.println(sugg);
	}
}

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NAowMTExCjEwMDAKMTAwMAoxMDAw

4
0111
1000
1000
1000