题解 | #合并表记录#

import sys

n = int(input())
dic = {}

for i in range(n):
    key,value = map(int,input().split())    #数值转换
    #dic[key] = dic.get(key,0) + value
    if key not in dic.keys():    #若从来没出现过，新增
        dic[key] = value
    else:                       #若出现过，求和
        dic[key] +=  value
for each in sorted(dic):     #排序
    print(each, dic[each])