#include<bits/stdc++.h>
using namespace std;
 map<int,int> mp;
int main()
{
    int n;
    cin>>n;
   
    for(int i=1;i<=n;i++)
    {
        int id,val;cin>>id>>val;
        mp[id]+=val;
    }
    for(auto x: mp)
    {
        cout<<x.first<<" "<<x.second<<endl;
    }
}

#牛客春招刷题训练营#https://gw-c.nowcoder.com/api/sparta/jump/link?link=https%3A%2F%2Fwww.nowcoder.com%2Fdiscuss%2F726480854079250432

//一开始内存超了,这给我搞懵了,这么玩是吧,别怪我直接map启动了

//简单来说就是遇到数组存不下的数,就要考虑用哈希map的写法了