public class StackOfStrings {

	private class Node {
		String item;
		Node next;
	}

	private Node first = null;
	private int size = 0;

	public boolean isEmpty() {
		return first == null;
	}
/*
	public void STackOfStrings() {

	}
*/

	public void push(String item) {
		Node oldfirst = first;
		first = new Node();
		first.item = item;
		first.next = oldfirst;
		size++;
	}

	public String pop() {
		String i = first.item;
		first = first.next;
		size--;
		return i;
	}

	public int size() {
		return size;
	}

}