#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

bool compare(pair<int,int> a,pair<int,int> b){
    if (a.second != b.second)
        return a.second < b.second;
    return a.first < b.first;
}

int main() {
    int n;
    cin >> n;
    int cnt = 1;
    vector<pair<int,int>> v(n);
    for (int i = 0;i < n;i++) {
        cin >> v[i].first >> v[i].second;
    }
    sort(v.begin(),v.end(),compare);
    int end_time = v[0].second;
    for (int i = 1;i < n;i++) {
        if (v[i].first < end_time) {
            continue;
        }
        if (v[i].first >= end_time) {
            cnt++;
            end_time = v[i].second;
        }
    }
    cout << cnt;
    return 0;
}