n = int(input())

mp = {}
name = []
for i in range(n):
    a, b = input().split()
    if mp.get(a) == None:
        mp[a] = 0
    if mp.get(b) == None:
        mp[b] = 0
    mp[a] += 1
    name.append(b)

for str in name:
    if mp[str] == 0:
        print(str)
    mp[str] += 1