using System;

public class Program

{

    public static void Main()

    {

        ListNode l = new ListNode(2);

        l.next = new ListNode(4);

        l.next.next = new ListNode(3);

        ListNode k = new ListNode(5);

        k.next = new ListNode(6);

        k.next.next = new ListNode(4);

        var result = AddTwoNumbers(l, k);

        Console.WriteLine("\n");

        Print(result);

    }

    static ListNode AddTwoNumbers(ListNode l1, ListNode l2) {

        int sum = 0, remainder = 0, val = 0;

        ListNode result =  new ListNode(0);

        ListNode current = result;

        while(l1 != null || l2 != null)

        {

            var x = (l1 != null ? l1.val : 0);

            var y = (l2 != null ? l2.val : 0);

            sum = (remainder + x + y);

            remainder = (sum >= 10 ? 1 : 0);

            val = (sum >= 10 ? (sum - 10) : sum);

            current.next = new ListNode(val);

            current = current.next;

            if(l1 != null)

                l1 = l1.next;

            if(l2 != null)

                l2 = l2.next;

            Console.WriteLine(">> result.next.val = {0} and current.val = {1}", result.next.val, current.val);

        }

        if(remainder > 0)

            current.next = new ListNode(remainder);

        return result.next;

    }

    static void Print(ListNode l)

    {

        while (l != null)

        {

            Console.WriteLine(l.val);

            l = l.next;

        }

    }

    public class ListNode

    {

        public int val;

        public ListNode next;

        public ListNode(int x)

        {

            val = x;

        }

    }

}