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

using namespace std;

int main()
{
    int n, i, out = 0;
    cin >> n;

    vector<pair<int, int>> foglalasok(n);
    vector<bool> van(n, 1);
    for (i = 0; i < n; i++) {
        cin >> foglalasok[i].first >> foglalasok[i].second;
    }

    sort(foglalasok.begin(), foglalasok.end(), [](pair<int, int> a, pair<int, int> b) {
        if (a.second == b.second) {
            return a.first < b.first;
        }
        else {
            return a.second < b.second;
        }
    });
   
    while (out != n && foglalasok.size() > 0) {
        int last = foglalasok[0].second;
        i = 1;
        while (i < foglalasok.size()) {
            if (foglalasok[i].first == last && van[i]) {
                van[i] = 0;
                last = foglalasok[i].second;
            }
            i++;
        }
        out++;
    }
    cout << out;
}