import MyStack;
import MyArrStack;
import MyListStack;

class StackTest {
    public static void main(String[] args) {
        MyStack s;

	s = new MyArrStack();
	s.push ("first"); s.push ("second");
	while (!s.empty()) System.out.println(s.pop());

        s = new MyListStack();
	s.push ("first"); s.push ("second");
	while (!s.empty()) System.out.println(s.pop());
    }
}