N = int(input())
A = [0]*N
B = [0]*N
for i in range(N):
    a,b = map(str, input().split())
    A[i] = a
    B[i] = b

A = set(A)
L = set([])
for i in B:
    if i in A or i in L:
        continue
    print(i)
    L.add(i)