public class zad9 {
	public static String rewrite (String in){

		if (in.length()<= 1){
			return in;
		}

		return rewrite (in.substring(1)) + in.charAt(0);
	}

	public static void main(String[] args) {
		String q = "4321";

		System.out.println(rewrite(q));
	}

}