public class Main{

    public static void main(String args[]){
	Stack s = new Stack(5);

	for (int i=0;i<10;i++){
	    try{
		s.push(new Integer(i));
	    } catch (Exception e) {
		System.out.println("OVERFLOW!");
		break;
	    }
	}

	for (int i=0;i<10;i++){
	    try{
		System.out.println(s.pop());
	    } catch (Exception e) {
		System.out.println("UNDERFLOW!");
		break;
	    }
	}

    }
}