using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, k) = (c[0], c[1]);
        var h = NList;
        var checkset = new HashSet<long>{ n };
        var ngset = new HashSet<long>();
        foreach (var hi in h)
        {
            for (var i = Math.Max(1, hi - 100); i <= hi; ++i) checkset.Add(i);
            ngset.Add(hi);
        }
        var checklist = new List<long>(checkset);
        checklist.Sort();
        for (var i = checklist.Count - 1; i >= 0; --i)
        {
            var cur = checklist[i];
            if (!ngset.Contains(cur))
            {
                if ((ngset.Contains(cur + 1) && ngset.Contains(cur + 6)) ||
                    (ngset.Contains(cur + 2) && ngset.Contains(cur + 5)) ||
                    (ngset.Contains(cur + 3) && ngset.Contains(cur + 4)))
                {
                    ngset.Add(cur);
                }
            }
            if (ngset.Contains(cur) && ngset.Contains(cur + 1) && ngset.Contains(cur + 2) && ngset.Contains(cur + 3) && ngset.Contains(cur + 4) && ngset.Contains(cur + 5))
            {
                WriteLine("No");
                return;
            }
        }
        WriteLine(ngset.Contains(1) ? "No" : "Yes");
    }
}