n140.5

//
//  main.cpp
//  test
//
//  Created by Максим Бачурин on 04.02.17.
//  Copyright © 2017 Максим Бачурин. All rights reserved.
//

#include <iostream>
#include <stdio.h>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <utility>
#include <set>
#include <map>
#include <list>
#include <queue>
#include <iomanip>
#include <sstream>
#include <fstream>
using namespace std;
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((int)(x).size())
#define FILE "sum"
typedef vector<int> VI;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
const ll mod = 1e9 + 7;
//const double eps = 1e-9;
const int inf = 1e9;
//const double PI = 3.1415926535897932384626433832795;
const int N = 100005;

int d[101][101];

int main()
{
    //freopen(FILE".in", "r", stdin);
    //freopen(FILE".out", "w", stdout);
    ios_base::sync_with_stdio(0);
    int n;
    cin >> n;
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < n; j++)
        {
            int a;
            cin >> a;
            d[i][j] = a;
            if(!a && i != j)
                d[i][j] = inf;
        }
    }
    for(int k = 0; k < n; k++)
        for(int i = 0; i < n; i++)
            for(int j = 0; j < n; j++)
            {
                if(d[i][k] < inf && d[k][j] < inf)
                    d[i][j] = max(-inf, min(d[i][j], d[i][k] + d[k][j]));
            }
    for(int i = 0; i < n; i++)
    {
        if(d[i][i] < 0)
            return cout << "YES", 0;
    }
    cout << "NO";
    return 0;
}