#include <cstddef> #include <iostream> #include <map> using namespace std; int main() { size_t cnt; cin >> cnt; size_t key; size_t value; map<size_t, size_t> my_map; for(size_t i = 0; i < cnt; ++i){ cin >> key >> value; my_map[key] += value; } for(auto iter : my_map){ cout << iter.first << " " << iter.second << endl; } return 0; } // 64 位输出请用 printf("%lld")