t111541

import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] used = new int[n];
        int [][] matrix = new int [n][n];


        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                int a = in.nextInt();
                matrix[i][j] = a;
            }
        }
        DFS(0, matrix, used, n);

        for (int i = 0; i < n; i ++)
            if (used[i] == 0) {
                is_tree = false;
                break;
            }
        if (is_tree)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
    public static boolean is_tree = true;
    public static void DFS(int v, int [][] matrix, int [] used, int n){
        if (used[v] == 2) {
            is_tree= false;
        } else {
            used[v] = 1;
            for (int i = 0; i < n; i++) {
                if (matrix[v][i] == 1 && used[i] != 1)
                     DFS(i, matrix, used, n);
            }
            used[v] = 2;
        }
    }
}