while True:
try:
n = int(input())
d = {}
for i in range(n):
a, b = input().strip().split()
if a in d:
d[a] += int(b)
else:
d[a] = int(b)
l = [int(i) for i in d.keys()]
# l.sort()
for i in sorted(l):
print(str(i) + ' ' + str(d[str(i)]))
except:
break