#include<bits/stdc++.h>
using namespace std;
int n,m,k;
char a[701][701];
int fx[8]={0,1,0,-1,1,-1,1,-1};
int fy[8]={1,0,-1,0,-1,-1,1,1};
 
void dfs(int x,int y){
    a[x][y]='0';
    for(int i=0;i<=7;i++){
        int tx=x+fx[i];
        int ty=y+fy[i];
        if(tx>=1&&ty>=1&&tx<=n&&ty<=n&&a[tx][ty]=='1'){
            dfs(tx,ty);
        }
                 
         
    }   
}
int main(){
    cin>>n;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            cin>>a[i][j];
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){   
            if(a[i][j]=='1'){
                k++;
                dfs(i,j);
            }
             
        }
    }
  
    cout<<k;
    return 0;
}
 
/**************************************************************
	Problem: 2068
	User: hulaoshi
	Language: C++
	Result: Accepted
	Time:263 ms
	Memory:5584 kb
****************************************************************/