//  Movie Festival

#include<bits/stdc++.h>

using namespace std;
using ll = long long;

int main() {
    int n; cin >> n;
    vector<pair<ll, ll>> movies(n);
    for (auto &p: movies) {
        ll a, b; cin >> a >> b;
        p = {b, a};
    }
    int count = 0;
    int current_time = 0;
    std::sort(movies.begin(), movies.end());
    for (auto &[end, start]: movies) {
        if (start >= current_time) {
            current_time = end;
            count++;
        }
    }

    cout << count << endl;

    return 0;
}