t111541

import java.util.Scanner;

public class t111541 {

    public static int[][] graph;
    public static int[] used;
    public static boolean tree = true;

    public static void dfs(int x) {
        if (used[x] == 2) {
            tree = false;
        } else {
            used[x] = 1;
            for (int i = 0; i < graph.length; i++) {
                if (graph[x][i] == 1 && used[i] != 1)
                    dfs(i);
            }
            used[x] = 2;
        }
    }

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

        graph = new int[n][n];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                graph[i][j] = in.nextInt();
            }
        }
        used = new int[n];
        dfs(0);
        for (int i = 0; i < n; i ++)
            if (used[i] == 0) {
                tree = false;
                break;
            }
        if (tree)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}