#include <bits/stdc++.h>

using namespace std;

int n;
int main() {
    cin >> n;
    int maxCount = -1;
    int count = 0;
    vector<pair<int, int>> a(n + 1);
    for (int i = 1; i <= n; i++) {
        cin >> a[i].first >> a[i].second;
    }
    bool visited[n + 1] = {false};
    int prev_end = -1;
    sort(a.begin(), a.end(), [](pair<int, int> a, pair<int, int> b) {
        return a.second < b.second;
    });
    for(int i = 1; i <= n; i++) {
        if (a[i].first > prev_end) {
            prev_end = a[i].second;
            count++;
        }
    }
    cout << count;
}