N = int(input())
l = [[] for _ in range(2*N)]
name = []
for _ in range(N):
    a,b = map(str,input().split())
    if a not in name:
        name.append(a)
    if b not in name:
        name.append(b)
    for i in range(len(name)):
        if name[i] == a:
            n = i
        if name[i] == b:
            m = i
    l[n].append(m)

for i in range(len(l)):
    if i == len(name):
        break
    if l[i] == []:
        print(name[i])