n=int(input())
AB=[list(map(str,input().split())) for _ in range(n)]

cheater,allperson=[],[]
for a,b in AB:
    cheater.append(a)
    allperson.append(a)
    allperson.append(b)
nocheater=set(allperson)
for c in cheater:
    if c in nocheater:
        nocheater.remove(c)
print(*nocheater,sep="\n")