#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<cctype>
#include<vector>
#include<queue>
#include<map>
#include<utility>
using namespace std;
char ar[100][100];
void floodfill(int a,int b,int m)
{
    int x,y;
    ar[a][b]='?';
    for(x=-1;x<4;x++){
        for(y=-1;y<4;y++){
		int newx=x+a,newy=y+b;
            if((newx>=0)&&(newx<m)&&(newy>=0)&&(newy<m)){
                if(ar[newx][newy]==1)floodfill(newx,newy,m);
            }
        }
    }
}
int main()
{
    int i,j,k,l,m,n,count=0;
	while(scanf("%d",&m)==1){
		count=0;
    for(i=0;i<m;i++){
		cin>>ar[i];
    }
    for(k=0;k<m;k++){
        for(l=0;l<m;l++){
            if(ar[k][l]==1){
            	floodfill(k,l,m);
                count++;
            }
        }
    }
    printf("%d\n",count);
	}return 0;
}