#class Node:
#  def __init__(self, value, next=None):
#    self.val = value
#    self.next = next

class Solution:
  def reverse(self, head):

    node = head
    prev = None
    
    while node.next:
      next_node = node.next
      node.next = prev
      prev = node
      node = next_node
    
    node.next = prev
    return node