题解 | #合并表记录#

import sys

input_data = sys.stdin.read().split()

n = int(input_data[0])

D = {}

for i in range(1,n*2,2):
    index = int(input_data[i])
    value = int(input_data[i+1])
    if index in D.keys():
        D[index] = D[index] + value
    else:
        D[index] = value

for index in sorted(D.keys()):
    print(index,D[index])