ソースコード
#include <bits/stdc++.h>
using namespace std;
long long int N, a, b, i;
vector<pair<long long, long long>> p, q;
int main(){
scanf("%lld", &N);
p.push_back(make_pair(1145141919810LL, 1145141919810LL));
for(; i < N; ++i){
scanf("%lld%lld", &a, &b);
p.push_back(make_pair(a, b));
}
sort(p.begin(), p.end());
a = p[0].first;
b = p[0].second;
for(i = 1; i <= N; ++i){
if(a != p[i].first){
q.push_back(make_pair(b, a));
a = p[i].first;
b = p[i].second;
}else{
b += p[i].second;
}
}
cout << (q.end() - 1)->second << endl;
return 0;
}