using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Diagnostics;
using System.Numerics;
using Enu = System.Linq.Enumerable;

public class Program
{
    static readonly int C = 4;
    int N, M;
    List<int>[] E;

    public void Solve()
    {
        N = Reader.Int();
        M = Reader.Int();
        E = Enu.Range(0, N).Select(i => new List<int>()).ToArray();
        Array.ForEach(Reader.IntTable(M), e => { E[--e[0]].Add(--e[1]); E[e[1]].Add(e[0]); });
        var random = new Random(0);
        int[] color = new int[N];

        for (int sim = 0; sim < 200; sim++)
        {
            for (int i = 1; i < N; i++)
                color[i] = 1 << random.Next(C);
            if (Search(color)) { Console.WriteLine("YES"); return; }
        }

        Console.WriteLine("NO");
    }

    private bool Search(int[] color)
    {
        var que = new Queue<int>();
        var seen = new bool[N, 1 << C];
        que.Enqueue(0); que.Enqueue(0);

        while (que.Count > 0)
        {
            int a = que.Dequeue(), mask = que.Dequeue();
            foreach (int b in E[a])
            {
                if (b == 0 && mask == (1 << C) - 1) return true;
                int nextMask = mask | color[b];
                if (nextMask != mask && !seen[b, nextMask])
                {
                    seen[b, nextMask] = true;
                    que.Enqueue(b); que.Enqueue(nextMask);
                }
            }
        }
        return false;
    }

}

class Entry { static void Main() { new Program().Solve(); } }
class Reader
{
    static TextReader reader = Console.In;
    static readonly char[] separator = { ' ' };
    static readonly StringSplitOptions op = StringSplitOptions.RemoveEmptyEntries;
    static string[] A = new string[0];
    static int i;
    static void Init() { A = new string[0]; }
    public static void Set(TextReader r) { reader = r; Init(); }
    public static void Set(string file) { reader = new StreamReader(file); Init(); }
    public static bool HasNext() { return CheckNext(); }
    public static string String() { return Next(); }
    public static int Int() { return int.Parse(Next()); }
    public static long Long() { return long.Parse(Next()); }
    public static double Double() { return double.Parse(Next()); }
    public static int[] IntLine() { return Array.ConvertAll(Split(Line()), int.Parse); }
    public static int[] IntArray(int N) { return Range(N, Int); }
    public static int[][] IntTable(int H) { return Range(H, IntLine); }
    public static string[] StringArray(int N) { return Range(N, Next); }
    public static string[][] StringTable(int N) { return Range(N, () => Split(Line())); }
    public static string Line() { return reader.ReadLine().Trim(); }
    static string[] Split(string s) { return s.Split(separator, op); }
    static T[] Range<T>(int N, Func<T> f) { var r = new T[N]; for (int i = 0; i < N; r[i++] = f()) ; return r; }
    static string Next() { CheckNext(); return A[i++]; }
    static bool CheckNext()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return CheckNext();
        A = Split(line);
        i = 0;
        return true;
    }
}