import java.util.*;
import java.lang.*;

class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
	String ab="abc";
	System.out.println(reverse(ab));

	}

    public static String reverse(String s) {
    if (s.length() <= 1) { 
        return s;
    }
    return reverse(s.substring(1, s.length())) + s.charAt(0);
}




}