using System;

class Program
{
    static void Main(string[] args)
    {
        var problem = new Problem();
        problem.PrepareTestCase1();
        problem.Solve();

        problem = new Problem();
        problem.PrepareTestCase2();
        problem.Solve();

        problem = new Problem();
        problem.PrepareTestCase3();
        problem.Solve();

        Console.WriteLine("Press any key...");
        Console.ReadKey(true);
    }
}

public class ListNode
{
    public int Value;
    public ListNode Next;
    public ListNode(int value)
    {
        Value = value;
    }
}

public class LinkedList
{
    public int Length = 0;
    public ListNode Head = null, Tail = null;

    public void Add(int value)
    {
        if (Head == null)
        {
            Head = new ListNode(value);
            Tail = Head;
        }
        else
        {
            Tail.Next = new ListNode(value);
            Tail = Tail.Next;
        }
        Length++;
    }

    public void Add(LinkedList list)
    {
        if (Head == null)
        {
            Head = list.Head;
            Tail = Head;
        }
        else
        {
            Tail.Next = list.Head;
            Tail = list.Tail;
        }
        Length += list.Length;
    }
}

public class Problem
{
    private LinkedList listA = new LinkedList(), listB = new LinkedList();

    private ListNode getIntersectionNode()
    {
        if (listA == null || listB == null)
            return null;

        if (listA.Tail != listB.Tail)
            return null; // both list must end with the same node if they intersect with each other

        var diff = Math.Abs(listA.Length - listB.Length);
        if (listA.Length > listB.Length)
            while (diff-- > 0)
                listA.Head = listA.Head.Next; // skip listA's head if listA has more elements than listB
        else
            while (diff-- > 0)
                listB.Head = listB.Head.Next; // skip listB's head if listB has more elements than listA

        while (listA.Head != listB.Head) // while not intersect
        {
            listA.Head = listA.Head.Next;
            listB.Head = listB.Head.Next;
        }

        return listA.Head;
    }

    public void Solve()
    {
        var intersectionNode = getIntersectionNode();
        Console.WriteLine("intersection = {0}", intersectionNode != null ? intersectionNode.Value.ToString() : "N/A");
    }

    public void PrepareTestCase1()
    {
        var intersection = new LinkedList();
        intersection.Add(8);
        intersection.Add(4);
        intersection.Add(5);

        listA.Add(4);
        listA.Add(1);
        listA.Add(intersection);

        listB.Add(5);
        listB.Add(0);
        listB.Add(1);
        listB.Add(intersection);
    }

    public void PrepareTestCase2()
    {
        var intersection = new LinkedList();
        intersection.Add(2);
        intersection.Add(4);

        listA.Add(0);
        listA.Add(9);
        listA.Add(1);
        listA.Add(intersection);

        listB.Add(3);
        listB.Add(intersection);
    }

    public void PrepareTestCase3()
    {
        listA.Add(2);
        listA.Add(6);
        listA.Add(4);

        listB.Add(1);
        listB.Add(5);
    }
}