n = int(input())
S = set()
A = []
d = {}
for i in range(n):
    a, b = map(str, input().split())
    S.add(a)
    S.add(b)
    A.append(a)
    if b not in d:
        d[b] = i

for a in A:
    S.discard(a)

X = []
for x in S:
    X.append((d[x], x))
X.sort()
for _, x in X:
    print(x)