题解 | #合并表记录#

a = int(input())
b = {}
for i in range(a):
    key = input().split(" ")
    k = int(key[0])
    v = int(key[1])
    try:
        b[k] += v
    except KeyError:
        b[k] = v

# 按键升序排序并输出
for k in sorted(b):
    print(k, b[k], end="\n")