#include<bits/stdc++.h>
using namespace std;
int n;
int t;
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&&tx<=n&&ty>=1&&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'){
    			dfs(i,j);
    			t++;
    		}
    	} 
    }
    cout<<t<<endl;
	return 0;
}

/**************************************************************
	Problem: 2068
	User: zengdongxin
	Language: C++
	Result: Accepted
	Time:263 ms
	Memory:6276 kb
****************************************************************/