#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

struct Talk {
    int start;
    int end;
};

bool compareTalks(const Talk& talk1, const Talk& talk2) {
    return talk1.start < talk2.start;
}

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

    vector<Talk> talks(n);
    for (int i = 0; i < n; i++) {
        cin >> talks[i].start >> talks[i].end;
    }

    sort(talks.begin(), talks.end(), compareTalks);

    vector<int> schedule(n);
    int daysNeeded = 1;
    int currentDay = talks[0].end;

    schedule[0] = currentDay;
    for (int i = 1; i < n; i++) {
        if (talks[i].start > currentDay) {
            // This talk cannot be held on the same day as the previous one
            currentDay = talks[i].end;
            daysNeeded++;
        } else {
            // This talk can be held on the same day as the previous one
            currentDay = max(currentDay, talks[i].end);
        }
        schedule[i] = currentDay;
    }

    cout << daysNeeded << endl;

    return 0;
}