n=int(input())

keys = set()
vals = set()
orders = {}
for i in range(n):
    a,b=input().split()
    keys.add(a)
    vals.add(b)
    if b not in orders:
        orders[b] = i

for b, i in sorted(orders.items(), key=lambda x:x[1]):
    if b not in keys:
        print(b)