#include<bits/stdc++.h>
using namespace std;
int main(){
	int a[5][205],i,j,n,max,x;
	cin>>n; 
	for(i=0;i<=n;i++){
		for(j=0;j<=n;j++){
			cin>>a[i][j];
		}
	}   
	for(i=0;i<n;i++){
		for(j=0;j<n;j++){
			if(x=a[i][j+1]){
			   n++;	
			}
			if(x=a[i+1][j]){
			   n++;
			}
		}	
	}
	return 0;
}
/**************************************************************
	Problem: 1999
	User: lijinkai
	Language: C++
	Result: Wrong Answer
****************************************************************/