题解 | #合并表记录#

times = int(input())
data_dict = {}
for time in range(times):
    arr_data = input().split(' ')
    if data_dict.get(int(arr_data[0])) is None:
        data_dict[int(arr_data[0])] = int(arr_data[1])
    else:
        data_dict[int(arr_data[0])] += int(arr_data[1])


for key,value in sorted(data_dict.items(),key=lambda s:s[0]):
    print(key,value,sep=' ')