using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Node<int> myList = Build(new Node<int>(0));

        int count = Count(myList, 2);

        Console.WriteLine(count);

    }

    public static int Count(Node<int> head, int n)

    {

        int ans = 0;

        Node<int> current = head;

        while(current != null)

        {

            if(current.val == n) ans++;

            current = current.next;             

        }

        return ans;         

    }

    public class Node<T>

    {

        public T val;

        public Node<T> next;

        //public Node<T> prev;

        public Node(T v) {val = v;}

    }

    public static Node<int> Build(Node<int> head)

    {

        // builds 4 node values

        Node<int> current = head;

        current.val = 1;

        for(int i = 2; i < 4; i++)

        {

            Node<int> n = new Node<int>(i);

            current.next = n;

            current = current.next;             

        }   

        return head;

    }

    public static List<int> Build()

    {

        List<int> myList = new  List<int>();

        for(int i = 1; i < 4; i++)

        {

            myList.Add(i);

        }   

        return myList;

    }

​

}