import java.util.Iterator;

public class Bag<Item> implements Iterable<Item>

{

    private Node first;

    private int N;

    private class Node

    {

        Item item;

        Node next;

    }//end class Node

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

    public int size(){return N;}

    public void add(Item item)

    {

        Node oldfirst=first;

        first=new Node();

        first.item=item;

        first.next=oldfirst;

        N++;

    }//end add

   

    public Iterator<Item> iterator()

    {return new ListIterator();}

   

    private class ListIterator implements Iterator<Item>

    {

        private Node current=first;

        public boolean hasNext(){return current!=null;}

        public void remove(){}

        public Item next()

        {

            Item item=current.item;

            current=current.next;

            return item;

        }//end next

    }//end Class ListIterator

   

    public static void main(String[] args)

    {

        Bag<String> b=new Bag<String>();

        while(!StdIn.isEmpty())

        {

            String item=StdIn.readString();

            b.add(item);

        }//end while

        for(String item:b)

            StdOut.print(item+" ");

    }//end main

   

   

}