n, a = [], {}
while True:
    try:
        n.append(tuple(input().split(' ')))
    except:
        break
n.pop(0)
n = sorted(n, key=lambda x:int(x[0]))
for i in n:
    a[i[0]] = 0
for i in n:
    a[i[0]] += int(i[1])
for k, v in a.items():
    print(k, v)