upa2.cpp

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

int main(){

    int n;
    cin >> n;

    vector<pair<int,int>> v;

    for(int i=0; i<n; i++){

        int c,p;
        cin >> c >> p;

        v.push_back({c,1});
        v.push_back({p,-1});
    }

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

    int qnt = 0, maxQnt = 0, instanteAnterior = -1;

    for(int i = 0; i<v.size(); i++){

        int instante = v[i].first, valor = v[i].second;

        if(instanteAnterior != instante) maxQnt = max(maxQnt, qnt);
        qnt += valor;
        instanteAnterior = instante;
    }

    maxQnt = max(qnt, maxQnt);

    cout << maxQnt*20 << "\n";
}