class ListItem {

    String data;
    ListItem next;

}


public class ListWithLinks2 {

    // Instance variables.
    ListItem front = null;
    ListItem rear = null;

    // To keep track of the size.
    int numItems = 0;


    public void add (String s)
    {
	if (front == null) {
            // The special case of an empty list needs to be handled differently.
	    front = new ListItem ();
	    front.data = s;
	    rear = front;
	    rear.next = null;
	}
	else {
            // Just like before:
            ListItem nextOne = new ListItem ();
	    nextOne.data = s;
	    rear.next = nextOne;
	    rear = nextOne;
	}    

	numItems ++;
    }


    public int size ()
    {
	return numItems;
    }

    
    public String get (int i)
    {
	if (i >= numItems) {
	    return null;
	}

        // Otherwise, count up to the i-th item.
	int count = 0;
	ListItem listPtr = front;

	while (count < i) {
	    listPtr = listPtr.next;
	    count ++;
	}

	return listPtr.data;
    }


    public boolean contains (String s)
    {
	if (front == null) {
	    return false;
	}

        // Start from the front and walk down the list. If it's there,
        // we'll be able to return true from inside the loop.
	ListItem listPtr = front;
	while (listPtr != null) {
	    if ( listPtr.data.equals(s) ) {
		return true;
	    }
	    listPtr = listPtr.next;
	}
	return false;
    }


    public void printList ()
    {
        // INSERT YOUR CODE HERE.
    }

}