using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using static System.Console;

class Program
{
    static void Main(string[] args)
    {
        new Program().Calc();
    }

    Scanner cin;

    public Program() { }

    bool chmax<T>(ref T a, T b) where T : IComparable<T> { if (a.CompareTo(b) < 0) { a = b; return true; } return false; }
    bool chmin<T>(ref T a, T b) where T : IComparable<T> { if (b.CompareTo(a) < 0) { a = b; return true; } return false; }

    class RangeEnd : IComparable
    {
        public int Start;
        public int End;

        public RangeEnd(int start, int end)
        {
            Start = start;
            End = end;
        }

        public int CompareTo(object obj)
        {
            return End - ((RangeEnd)obj).End;
        }
    }

    void Calc()
    {
        cin = new Scanner();

        int N = cin.nextInt();
        int M = cin.nextInt();

        List<RangeEnd> end = new List<RangeEnd>(M);

        for (int i = 0; i < M; ++i)
        {
            int A = cin.nextInt();
            int B = cin.nextInt();

            var rangeEnd = new RangeEnd(A, B);
            end.Add(rangeEnd);
        }

        int count = 0;
        int endIndex = 0;

        end.Sort();

        while (true)
        {
            int endFirst = end[endIndex].End;

            for (; endIndex < end.Count; ++endIndex)
            {
                if (end[endIndex].Start >= endFirst)
                {
                    break;
                }
            }

            ++count;

            if (endFirst == N || endIndex == end.Count)
            {
                break;
            }
        }

        WriteLine(count);
    }
}

public static class StringExtension
{
    public static char GetChar1(this string str, int indexOneBase)
    {
        return str[indexOneBase - 1];
    }
}

class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        if (s.Length == 0) return next();
        i = 0;
        return s[i++];
    }

    public int nextInt()
    {
        return int.Parse(next());
    }
    public int[] ArrayInt(int N, int add = 0)
    {
        int[] Array = new int[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextInt() + add;
        }
        return Array;
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public long[] ArrayLong(int N, long add = 0)
    {
        long[] Array = new long[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextLong() + add;
        }
        return Array;
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }


    public double[] ArrayDouble(int N, double add = 0)
    {
        double[] Array = new double[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextDouble() + add;
        }
        return Array;
    }
}


Measured memory_bytes: 22092