题解 | #合并表记录#

a = int(input())
temp={}
j=0
for i in range(a):
    line = input().split()
    key=int(line[0])
    value=int(line[1]) 
    if key in temp.keys():
        temp[key] = temp[key]+ value
    else:
        temp[key] = value

for i in sorted(temp):
    print(int(i),temp[i])