N = int(input())

bad = [0]*N
cand = [0]*N#答えの候補
for i in range(N):
    b, c = list(input().split())
    bad[i] = b
    cand[i] = c

remove = set(bad)&set(cand)#見られただけかと思いきやカンニングもしてたやつら

already = {}

for c in cand:
    if c not in remove:
        if c not in already:
            print(c)
            already[c] = 0