#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long int ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
    return (ull)rng() % B;
}
inline double time() {
    return static_cast<long double>(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count()) * 1e-9;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n; cin >> n;
    vector<pair<int,int>> v(n);
    for (int i = 0; i < n; ++i) {
        cin >> v[i].first >> v[i].second;
    }
    sort(v.rbegin(), v.rend());
    int cnt = 0;
    int mx = -1;
    for (int i = 0; i < n; ) {
        if (mx < v[i].second) {
            cnt += 1;
            mx = v[i].second;
        }
        int a = v[i].first;
        while (i < n and v[i].first == a) {
            i += 1;
        }
    }
    cout << cnt << endl;
}