items = list(map(int, input().split(",")))
k = int(input())
link = []
head = 0
for i in items:
    link.append([i, len(link) + 1])
link[-1][1] = -1
...
...
p = head
while p != -1:
    print(link[p][0], end=",")
    p = link[p][1]