题解 | #合并表记录#

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

for i in range(n):
    k, v = (int(x) for x in input().split(" "))
    if k in map:
        map[k] += v
    else:
        map[k] = v

#按key排序
map = sorted(map.items())

for k, v in map:
    print(k, v)