/*************************************************************************
 *
 *      This is a stack implementation that extends the ArrayList class
 *
 *************************************************************************/

import java.util.*;

public class Stack<AnyType> extends ArrayList<AnyType> implements StackInterface<AnyType>
{
   public Stack()
   {
      super();
   }

 /**
   * Inserts an item onto the top of the stack.
   */
   public void push(AnyType x)
   {
      add(x);
   }

 /**
   *  Removes and returns the item at the top of this stack.
   */
   public AnyType pop( ) throws StackException
   {
      if(isEmpty())
         throw new StackException("Stack is empty");
      else
         return remove(size()-1);
   }

 /**
   *  Returns the top item without its removal
   */
   public AnyType peek() throws StackException
   {
      return get(size()-1);
   }

 /**
   *  Returns a string representation
   */
   public String toString()
   {
		StringBuffer str = new StringBuffer(super.toString());
		str.setCharAt(0,'<');
		str.setCharAt(str.length()-1,'>');
      return str.toString();
   }


   public static void main(String[] args)
   {
      Stack<Integer> stk = new Stack<Integer>();
      stk.push(1);
      stk.push(5);
      stk.push(10);
      System.out.println(stk);
	}

}



	/**              StackInterface           **/

interface StackInterface<AnyType>
{
 /**
   * Tests if the stack is empty.
   */
   public boolean isEmpty();

 /**
   *  Removes and returns the item at the top of this stack.
   */
   public AnyType pop() throws StackException;

 /**
   *  Returns the top item without its removal
   */
   public AnyType peek() throws StackException;

 /**
   * Inserts an item onto the top of the stack.
   */
   public void push(AnyType e) throws StackException;

 /**
   * Removes all items from the stack.
   */
   public void clear();
}


	/**              StackException           **/


class StackException extends RuntimeException
{
   public StackException(String name)
   {
      super(name);
   }

   public StackException()
   {
      super();
   }
}