public class Node
{
	private int data;
	private Node link;

	public Node()
	{
		data = 0;
		link = null;
	}

	public int getData()
	{
		return data;
	}

	public Node getLink()
	{
		return link;
	}

	public void setData(int d)
	{
		data = d;
	}

	public void setLink(Node l)
	{
		link = l;
	}
}
			

public class List
{
	private Node head;
	private int count;

	public List()
	{
		head = null;
		count = 0;
	}

	public boolean isEmpty()
	{
		return (count == 0);
	}

	public int getSize()
	{
		return count;
	}

	public int getElement(int index)
	{
		if(index < 0 || index > count) return -1;
		Node walker = head;
		for(int i = 0; i < index; i++)
			walker = walker.getLink();

		return walker.getData();
	}

	public String toString()
	{
		String str = "[";
		Node walker = head;
		while(walker != null)
		{
			str = str + " " + walker.getData();
			walker = walker.getLink();
		}

		return str+" ]";
	}

	public boolean search(int element)
	{
		Node walker = head;
		while(walker != null && walker.getData() != element)
			walker = walker.getLink();
		if(walker == null)
			return false;
		else
			return true;
	}

	public boolean insert(int element, int index)
	{
		if(index < 0 || index > count)
			return false;

		Node newNode = new Node();
		newNode.setData(element);

		if(index == 0)
		{
			newNode.setLink(head);
			head = newNode;
			count++;
			return true;
		}

		Node walker = head;
		for(int i = 0; i < index-1; i++)
			walker = walker.getLink();
		newNode.setLink(walker.getLink());
		walker.setLink(newNode);
		count++;
		return true;
	}

	public boolean delete(int index)
	{
		if(index < 0 || index > count-1)
			return false;
		if(index == 0)
		{
			head = head.getLink();
			count--;
			return true;
		}
		Node walker = head;
		for(int i = 0; i < index-1; i++)
			walker = walker.getLink();
		walker.setLink(walker.getLink().getLink());
		count--;
		return true;
	}
}
			

public class Stack extends List
{
	public Stack()
	{
		super();
	}

	public int top()
	{
		return getElement(0);
	}

	public boolean push(int e)
	{
		return insert(e, 0);
	}

	public boolean pop()
	{
		return delete(0);
	}
}
			

public class StackTest
{
	public static void main(String args[])
	{
		Stack s = new Stack();

		//push
		for(int i = 0; i < 11; i++)
			s.push(i);

		//toString
		System.out.println(s);

		//pop
		while(!s.isEmpty())
		{
			s.pop();
			System.out.println(s);
		}
	}
}