#include <fstream>
#include <algorithm>
using namespace std;

ifstream cin("int.in");
ofstream cout("int.out");

pair < int, int > v[50010];

int main()
{
    int n, nr = 0, lim = -2000000010;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> v[i].second >> v[i].first;
    }
    sort(v, v + n);
    for (int i = 0; i < n; ++i) {
        if (v[i].second >= lim) {
            ++nr;
            lim = max(v[i].first, lim);
        }
    }
    cout << nr;
    return 0;
}