#include <iostream>
#include <algorithm>

using namespace std;

struct Pair {
    int l, r;
} a[100500];

bool cmp(Pair p1, Pair p2) {
    return p1.r < p2.r;
}

int main() {
    int n;
    cin >> n;

    for (int i = 1; i <= n; i++)
        cin >> a[i].l >> a[i].r;

    sort(a + 1, a + n + 1, cmp);

    int last = 0, ans = 0;

    for (int i = 1; i <= n; i++) {
        if (a[i].l > last)
            ans++, last = a[i].r;
    }

    cout << ans;

    return 0;

}