#include <iostream>
using namespace std;

void dfs(int v, int **Array, int n, int *Array1)
{
    Array1[v] = 1;

    for (int i = 0; i < n; i++)
    {
        if (Array[v][i] == 1 && Array1[i] == 0)
            dfs(i, Array, n, Array1);
    }
}

int color[N];

void dfs(int v)
{
	color[v] = 1;
	for(int i=0; i < N; i++)
	{
	if(g[v][i] != -1 && color[i] == 1)
	cycle_find = true;
	color[v] = 2;
	}
}

int main()
{
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);

    int n;

    cin >> n;

    int **Array = new int *[n];

    for (int i = 0; i < n; i++)
        Array[i] = new int [n];

    int *Array1 = new int [n];

    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
            cin >> Array[i][j];

        Array1[i] = 0;
    }

    dfs(n - 1, Array, n, Array1);

    for (int i = 0; i < n; i++)
    {
        if (Array1[i] == 0)
        {
            cout << "NO" << endl;

            return 0;
        }
    }

    cout << "YES" << endl;

    return 0;
}