class Solution:
def EntryNodeOfLoop(self, pHead):
# write code here
mark=set()
curr=pHead
while curr:
if curr in mark: return curr
else: mark.add(curr)
curr=curr.next
class Solution:
def EntryNodeOfLoop(self, pHead):
# write code here
mark=set()
curr=pHead
while curr:
if curr in mark: return curr
else: mark.add(curr)
curr=curr.next