Movie Festival II

#include <bits/stdc++.h>

using namespace std;

struct Movie{
    int start, end;
    bool operator<(const Movie &a) const{
        if(end == a.end){
            return start<a.start;
        }
        return end<a.end;
    }
};

int n, k;
vector<Movie> mv;
multiset<int, greater<int>> person;
int ans;

int main(){
    //freopen("moviefestivalII.in", "r", stdin);

    cin >> n >> k;
    //mv.resize(n+1);
    for(int i=0; i<n; i++){
        int a, b;
        cin >> a >> b;
        mv.push_back({a, b});
    }
    sort(mv.begin(), mv.end());
    for(int i=0; i<k; i++){
        person.insert(0);
    }
    for(Movie m: mv){
        auto it = person.lower_bound(m.start);
        if(it == person.end()){
            continue;
        }
        person.erase(it);
        person.insert(m.end);
        ans++;
    }
    cout << ans << '\n';

    return 0;
}