// dsaI_17_15.java SJ

import fi.joensuu.cs.tra.*;
import java.util.LinkedList;

public class dsaI_17_15_skeleton {

	public static void main(String[] args) {

        // stack size
		int N = 10;
        if (args.length > 0)
            N = Integer.valueOf(args[0]);

        // elements to reverse
		int k = 3;
        if (args.length > 1)
            k = Integer.valueOf(args[1]);


		LinkedStack<String> S = new LinkedStack<String>();
		for (int i = 0; i < N; i++)
			S.push("a" + i);

		if (N <= 20)
			System.out.println(S);

		reverse_k(S, k);
		if (N <= 20)
			System.out.println(S);

	} // main()

    /**
     * 15. Write an algorithm that reverses the k topmost elements of a stack.
     * If there are ≤k ele- ments, algorithm reverses the whole stack. Use
     * either data structure library LinkedStack or Java API LinkedList. What
     * it the time complexity of your algorithm?
     **/
    public static <E> void reverse_k(LinkedStack<E> S, int k) {

        // TODO

	} // reverse_k



} // class dsaI_17_15