#include<bits/stdc++.h> using namespace std; int main() { int n; cin >> n; vector<pair<int, int>> arr; unordered_map<int, int> map; while(n--) { int key, val; cin >> key >> val; if (map.find(key) == map.end()) { map[key] = val; } else { map[key] += val; } } ...