11000번

11000

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

bool compare(pair<int,int> p1, pair<int,int> p2) {
        if(p1.second == p2. second) return p1.first < p2.first;
        else return p1.second < p2.second;
}

int main() {
    int n;
    vector<pair<int,int>> v;
    priority_queue<int, vector<int>, greater<int>> pq;
    cin>>n;
    for(int i=0; i<n; i++) {
        int a,b;
        cin>>a>>b;
        v.push_back(make_pair(a,b));
    }

    sort(v.begin(), v.end());

    for(int i = 0; i < v.size(); i++) {
        if(!pq.empty() && pq.top() <= v[i].first) {
            pq.pop();
            pq.push(v[i].second);
        } else {
            pq.push(v[i].second);
        }
    }
    cout<<pq.size();
}