Contest1230/C.cpp

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    while(cin >> n){
        int a[n][n];
        for(int i = 0; i < n; i++){
            for(int j = 0; j < n; j++){
                cin >> a[i][j];
            }
        }
        int flag = 0;
        for(int i = 0; i < n; i++){
            for(int j = 0; j < i; j++){
                if(a[i][j] != a[j][i]){
                    flag = 1;
                    break;
                }
            }
            if(flag == 1)break;
        }
        if(flag == 1){
            cout << "No!" << endl;
        }else {
            cout << "Yes!" << endl;
        }
    }
    return 0;
}