#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
using namespace std;

struct movie{
    int S, E;
    movie(){}
    movie(int a, int b) {
        S = a;
        E = b;
    }
    bool operator < (const movie &x) const {
        return E < x.E;
    }
};
int main()
{
    ios_base::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<movie> v;
    for(int i =0; i < n; ++i) {
        int a, b;
        cin >> a >> b;
        v.push_back(movie(a, b));
    }
    sort(v.begin(), v.end());
    int last_ending_time = v[0].E;
    int ret = 1;
    for(int i = 1; i < n; ++i) {
        if(last_ending_time <= v[i].S) {
            ++ret;
            last_ending_time = v[i].E;
        }
    }
    cout << ret << endl;
    return 0;
}



/*
 10
 404 882
 690 974
 201 255
 800 933
 525 819
 457 601
 461 978
 832 932
 699 804
 795 860
 */