CSES-1629 Movie Festival

#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define fi first
#define se second
#define INF LONG_LONG_MAX/1000
#define WA() cin.tie(0)->sync_with_stdio(0)
#define all(x) (x).begin(), (x).end()
#define int long long
#define PII pair<int, int>

signed main() { WA();
    int n; cin >> n;
    vector<pair<int, int>> v(n);
    for (auto &i : v) cin >> i.se >> i.fi;
    sort(all(v));

    int last = 0, cnt = 0;
    for (auto &i : v) if (last <= i.se) cnt++, last = i.fi;

    cout << cnt;
}