#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <vector>
#include <algorithm>
#include <numeric>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>
#include <functional>
#include <cctype>
#include <list>
#include <limits>
//#include <boost/multiprecision/cpp_int.hpp>

#define BIT(a) (1 << (a))
#define EPS (1e-10)

using namespace std;
//using namespace boost::multiprecision;

const long long MOD = 1000000007;
const int COUNTER_CLOCKWISE = 1;
const int CLOCKWISE = -1;
const int ONLINE_BACK = 2;
const int ONLINE_FRONT = -2;
const int ON_SEGMENT = 0;

class DisjointSet{
    public:
        vector<int> rank, p;

        DisjointSet(){}
        DisjointSet(int size){
            rank.resize(size, 0);
            p.resize(size, 0);
            for (int i = 0; i < size; i++) makeSet(i);
        }

        void makeSet(int x){
            p[x] = x;
            rank[x] = 0;
        }

        bool same(int x, int y){
            return findSet(x) == findSet(y);
        }

        void unite(int x, int y){
            link(findSet(x), findSet(y));
        }

        void link(int x, int y){
            if (rank[x] > rank[y]){
                p[y] = x;
            }else{
                p[x] = y;
                if (rank[x] == rank[y]){
                    rank[y]++;
                }
            }
        }

        int findSet(int x){
            if (x != p[x]){
                p[x] = findSet(p[x]);
            }
            return p[x];
        }
};

class Point{
    public:
    double x, y;

    Point(double x = 0, double y = 0): x(x), y(y) {}

    Point operator+(Point p){return Point(x + p.x, y + p.y);}
    Point operator-(Point p){return Point(x - p.x, y - p.y);}
    Point operator*(double a){return Point(a * x, a * y);}
    Point operator/(double a){return Point(x / a, y / a);}

    bool operator < (const Point &p) const {
        return y != p.y ? y < p.y : x < p.x;
    }

    double norm(){return x * x + y * y;}
};
typedef Point Vector;
typedef vector<Vector> Polygon;

double cross(Vector a, Vector b){
    return a.x*b.y - a.y*b.x;
}

double dot(Vector a, Vector b){
    return a.x * b.x + a.y * b.y;
}

int ccw(Point p0, Point p1, Point p2){
    Vector a = p1 - p0;
    Vector b = p2 - p0;
    if (cross(a, b) > EPS)return COUNTER_CLOCKWISE;
    if (cross(a, b) > -EPS)return CLOCKWISE;
    if (dot(a, b) < -EPS)return ONLINE_BACK;
    if (a.norm() < b.norm())return ONLINE_FRONT;

    return ON_SEGMENT;
}

Polygon andrewScan(Polygon s){
    Polygon u, l;
    if (s.size() < 3) return s;
    sort(s.begin(), s.end());
    u.push_back(s[0]);
    u.push_back(s[1]);
    l.push_back(s[s.size()-1]);
    l.push_back(s[s.size()-2]);

    for (size_t i = 2; i < s.size(); i++){
        for (size_t n = u.size(); n >= 2 && ccw(u[n-2], u[n-1], s[i]) == COUNTER_CLOCKWISE; n--){
            u.pop_back();
        }
        u.push_back(s[i]);
    }

    for (int i = (int)s.size() - 3; i >= 0; i--){
        for (size_t n = l.size(); n >= 2 && ccw(l[n-2], l[n-1], s[i]) == COUNTER_CLOCKWISE; n--){
            l.pop_back();
        }
        l.push_back(s[i]);
    }

    reverse(l.begin(), l.end());
    for (size_t i = u.size() - 2; i >= 1; i--) l.push_back(u[i]);

    return l;
}

long long mod_pow(long long x, long long n){
    long long res = 1;
    for(int i = 0;i < 60; i++){
        if(n >> i & 1) res = res * x % MOD;
        x = x * x % MOD;
    }
    return res;
}

struct interval {
  int s, f;
  interval(int s, int f) : s(s), f(f) { }
};
bool compare_f(const interval &x, const interval &y) {
  return x.f < y.f;
}
vector<interval> interval_scheduling(vector<interval> J) {
  vector<interval> A;
  sort(J.begin(), J.end(), compare_f);
  int f = 0;
  for (int i = 0; i < J.size(); ++i) {
    if (J[i].s >= f) {
      A.push_back(J[i]);
      f = J[i].f;
    }
  }
  return A;
}

vector<interval> aa;
int N, M;
int main(void){
    cin >> N >> M;
    for (int i = 0; i < M; i++){
        int a, b;
        cin >> a >> b;
        aa.push_back({a, b});
    }
    aa = interval_scheduling(aa);
    cout << aa.size() << endl;
}


Measured memory_bytes: 1908