
#include <stdio.h>#include <stdlib.h>int main(){int num = 0;int temp_key = 0;int temp_velue = 0;int key[1000] = {0};scanf("%d",&num);while(scanf("%d %d",&temp_key,&temp_velue)!=EOF){key[temp_key]+=temp_velue;}for(int i = 0;i<999;i++){if(key[i]!=0){printf("%d %d\n",i,key[i]);}}}
