#include <iostream>
using namespace std;
int main()
{int n, a[50][50],i,j;
cout<<"n="; cin>>n;
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
{cout<<"a["<<ï<<"]["<<j<<"]=";
cin>>a[i][j];}
//Afisarea elementelor de pe diagonala principală
for(i=1;i<=n;i++)
cout<<a[i][i]<<" "
cout<<endl;
return 0;
}