using System;

namespace ALGA {
	public class StringReverse {
		public static String string_reverse(String s) {
			if (s.Length == 0) return s;
			return s[s.Length - 1] + string_reverse(s.Substring(0, s.Length - 1));
		}

		public static bool is_palindrome(String s) {
			if (s.Length < 2) return true;
			if (s[0] != s[s.Length - 1]) return false;
			return is_palindrome(s.Substring(1, s.Length - 2));
		}
	}
}