package No400番台;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

public class Main{
	public static void main(String[] args) {
		solver();
	}

	static void solver() {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		ArrayList<Integer>[] e = new ArrayList[n];
		for (int i = 0; i < n; i++) {
			e[i] = new ArrayList<>();
		}
		for (int i = 0; i < m; i++) {
			int a = sc.nextInt() - 1;
			int b = sc.nextInt() - 1;
			e[a].add(b);
			e[b].add(a);
		}

		boolean ans = false;
		for (int i = 0; i < 200; i++) {
			Random rand = new Random();
			int[] col = new int[n];
			Arrays.fill(col, -1);
			for (int j = 1; j < n; j++) {
				col[j] = rand.nextInt(4);
			}
			boolean[][] dp = new boolean[1 << 4][n];
			dp[0][0] = true;
			for (int s = 0; s < (1 << 4) - 1; s++) {
				for (int v = 0; v < n; v++) {
					if (dp[s][v]) {
						for (int u : e[v]) {
							if (u != 0) {
								int t = s | (1 << col[u]);
								if (t > s) {
									dp[t][u] = true;
								}
							}
						}
					}
				}
			}
			for (int j = 1; j < n; j++) {
				if (dp[(1 << 4) - 1][j]) {
					for (int v : e[j]) {
						if (v == 0) {
							ans = true;
						}
					}
				}
			}
		}
		System.out.println(ans ? "YES" : "NO");
	}
}