using System;

public class Program

{

    public static void Main()

    {

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

        ls.Add(5);

        Console.WriteLine("Hello World");

    }

}

public class List<T>

{

    private int len;

    private Node<T> first;

    private Node<T> last;

    public List()

    {

        this.len = 0;

        this.first=null;

        this.last=null;

    }

    private Node<T> GetNd(int stps)

    {

        if(stps<0)

            return null;

        Node<T> pos=this.first;

        for(int i=0; i<stps && pos!=null ;i++)

            pos=pos.GetNext();

        return pos;

    }

    public T GetVal(int i)

    {

        if(i==this.len-1)

            return GetLast();

        return GetNd(i).GetValue(); //assuming that i exist

    }

    public T GetLast()

    {

        return this.last.GetValue();

    }

    public int GetSize()

    {

        return this.len;

    }

    public void SetVal(int i,T val)

    {

        if(i>=0 && i<this.len)

            GetNd(i).SetValue(val);

    }

    public void Insert(T val)

    {

        if(this.first==null)

        {

            this.first=new Node<T>(val);

            this.last = new Node<T>(val);

        }

        else

        {

            this.last.SetNext(new Node<T>(val));

            this.last=this.last.GetNext();

        }

        this.len++;

    }

    public void Insert(int i,T val)

    {

        if(i==this.len)

            Insert(val);

        else

        {

            Node<T> pos=GetNd(i);

            if(pos!=null)

            {

                Node<T> tmp=pos.GetNext();

                pos.SetNext(new Node<T>(val));

                pos.GetNext().SetNext(tmp);

                this.len++;

            }

        }

    }

    public void Remove()

    {

    }

    public override string ToString()

    {

        return Helper(this.first,0);

    }

    private string Helper(Node<T> pos,int cnt)

    {

        if(cnt==this.len-1)

            return pos.ToString();

        return pos.ToString()+Helper(pos.GetNext(),cnt++);

    }

}

​

​

​

// המחלקה חוליה

public class Node<T> 

{

    private T value;

    private Node<T> next;

    public Node (T value)

    {

        this.value=value;

        this.next=null;

    }

​

    public Node (T value, Node<T> next)

    {

        this.value=value;

        this.next=next;

    }

    public T GetValue()

    {

        return this.value;

    }

​

    public Node<T> GetNext()

    {

        return this.next;

    }

    public void SetValue (T value)

    {

        this.value=value;

    }

    public void SetNext(Node<T> next)

    {

        this.next=next;

    }

​

    public bool HasNext()

    {

       return this.next != null;

    }

    public override String ToString()

    {

        return this.value.ToString();

    }

}

​