#include<bits/stdc++.h>
using namespace std;
char mp[711][711];bool vis[711][711];
int dx[9]={0,1,-1,1,0,-1,0,1,-1},dy[9]={0,1,-1,0,1,0,-1,-1,1};
int m,n,ans;
struct Node{
	int x;int y;
};
void bfs(int x,int y){
	queue<Node>q;
	q.push({x,y});
	vis[x][y]=1;
	while(!q.empty()){
		Node c=q.front();
		q.pop();
		for(int i=1;i<=8;i++){
			int fx=c.x+dx[i];int fy=c.y+dy[i];
			if(fx>=1&&fx<=n&&fy>=1&&fy<=n&&vis[fx][fy]==0&&mp[fx][fy]!='0'){
				vis[fx][fy]=1;
				q.push({fx,fy});
			}else continue;
		}
	}
}
int main(){
	freopen("common.in","r",stdin);freopen("common.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			cin>>mp[i][j];
		}
	}
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			if(mp[i][j]!='0'&&vis[i][j]==0){
				bfs(i,j);
				ans++;
			}
		}
	}
	printf("%d",ans);
	return 0;
}