#Definition for singly-linked list.

class ListNode(object):

     def __init__(self, x):

         self.val = x

         self.next = None

class Solution(object):

    def addTwoNumbers(self, l1, l2):

        """

        :type l1: ListNode

        :type l2: ListNode

        :rtype: ListNode

        """

        nHead = ListNode(0)

        carry = 0

        head = nHead

        flag = 0

        while l1 or l2:

            node = ListNode(flag)

            print(node.val,node.next)

            if l1:

                node.val += l1.val

                l1 = l1.next

            if l2:

                node.val += l2.val

                l2 = l2.next

            flag = node.val // 10

            node.val %= 10

            head.next, head = node, node

            print(node.val,node.next,flag,head.val,head.next)

        print(head.val,nHead.val,nHead.next.val,nHead.next.next.val)

        return nHead.next

if __name__=="__main__":

    nl = ListNode(0)

    nl2 = ListNode(0)

    l0 = nl

    l1 = nl

    list1=[5,8,6,7]

    for x in list1:

        node = ListNode(0)

        node.val = x

        l0.next=node

        l0 = node

    print (nl2.next,nl.next.next.val,nl.next.next.next.val,l1.next.next.next.next.val)