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();
    static long[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, m) = (c[0], c[1]);
        var map = NArr(m);
        var pos = 0L;
        var time = 0L;
        for (var i = 0; i < m; ++i)
        {
            if (Math.Abs(map[i][1] - pos) > map[i][0] - time)
            {
                WriteLine("No");
                return;
            }
            time = map[i][0];
            pos = map[i][1];
        }
        WriteLine("Yes");
    }
}