static void Main()
{
StackLinkedList list = new StackLinkedList();
list.push(2);
//Console.WriteLine(list.pop());
Console.WriteLine(list.peek());
Console.WriteLine(list.pop());
list.push(3);
list.push(4);
list.push(5);
Console.WriteLine(list.pop());
Console.WriteLine(list.pop());
Console.WriteLine(list.pop());
}