#include <iostream>
using namespace std;
int v[21][21];
int main()
{
int n, i, j, suma=0;
cout << " n= "; cin >> n;
cout << " introdu " << n*n << " numere intregi \n";
for (i=1; i<=n; ++i)
{
for (j=1; j<=n; ++j)
{
cin >> v[i][j];
if (i<j && i+j>n+1) suma+=v[i][j];
}
}
cout << " suma VEST= " << suma << "\n";
return 0;
}