题解 | #合并表记录#

import sys

n = int(input())
a = {}
for i in range(n):
    k_v = input().split(' ')
    if not int(k_v[0]) in a.keys():
        a[int(k_v[0])] = int(k_v[1])
    else:
        a[int(k_v[0])] += int(k_v[1])
keys = list(a.keys())
keys.sort()
for b in keys:
    print(f'{b} {a[b]}')