class Solution(object):
def sortList(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
res=[]
while head:
res.append(head.val)
head=head.next
res.sort()
p=ListNode(0)
s=p
for r in res:
p.next=ListNode(r)
p=p.next
return s.next