题解 | #合并表记录#

import sys

#for line in sys.stdin:
#    a = line.split()
#   print(int(a[0]) + int(a[1]))
n=int(input())
dict={}
tuple=()
i=0
while i<n:
    s=input()
    i+=1
    key=int(s.split(" ")[0])
    value=int(s.split(" ")[1])
    if key in dict.keys():
        dict[key]+=value
    else:
        dict[key]=value
keys=dict.keys()
keys=sorted(keys)
#print(keys)
for key in keys:
    print(key,dict[key])