#include<iostream>
#include<cstdio>
#include<cstring>
#include<iomanip>
#include<cmath>
#include<cstdlib>
#include<algorithm>
using namespace std;
short int mat[2001][2001];
int main(){
// cout<<"hi";
int n;
scanf("%d",&n);
int i;
int arr[1001],top;
int ans=0;
for(i=1;i<=n;i++){
top=0;
char ch;
int j;
getchar();
for(j=1;j<=n;j++){
ch=getchar();
if(ch=='0')
continue;
else{
top++;
arr[top]=j;
//printf("top%darr%d ",top,arr[top]);
if(mat[i][j]==1)
{
mat[i][j]=-1;
mat[j][i]=-1;
ans-=2;
}
if(mat[i][j]==0){
mat[i][j]=-1;
mat[j][i]=-1;
}
}
}int u,y;
//for(u=1;u<=top;u++)
//printf("%d ",arr[u]);
for(u=1;u<top;u++)
for(y=u+1;y<=top;y++){
if(mat[arr[u]][arr[y]]==0){
mat[arr[u]][arr[y]]=1;
mat[arr[y]][arr[u]]=1;
ans+=2;
}
}
//printf("ansis %d",ans);
}printf("%d\n",ans);
cin.get();
cin.get();
}/*
9
011100000
101100000
110100000
111000001
000000000
000000100
000001000
000000001
000100010*/
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