n = int(input())

s1 = set()
s2 = set()
name_b = []
for i in range(n):
    a, b = input().split()
    s1.add(a)
    s2.add(b)
    if b not in name_b:
        name_b.append(b)

ans = s2 - s1

for n in name_b:
    if n in ans:
        print(n)