#!/usr/bin/python3

#建立循环链表。

class Node():
def init(self,data=None):
self.data=data
self.next=None

n1=Node(5)
n2=Node(15)
n3=Node(25)
n1.next=n2
n2.next=n3
n3.next=n1
ptr=n1
counter=1
while counter<=6:
print(ptr.data)
ptr=ptr.next
counter+=1