import java.math.BigInteger;
import java.util.Scanner;

 class Main {
    public static BigInteger reverse(BigInteger num){
        return new BigInteger(new StringBuilder(num+"").reverse().toString());
    }
    public static void main(String[] args) {
        System.out.println("Дай мне число, больше ста!");
        Scanner in = new Scanner(System.in);
        BigInteger bi = in.nextBigInteger();
        byte cont = 0;
        do {
            BigInteger rev = reverse (bi);
            BigInteger sum  = bi.add(rev);
            int x = sum.toString().length();
            if (x % 2 == 0){
                int half = x / 2;
                double result = Math.pow(10,half);
                int i = (int) result;
                //bi = sum % half;
                BigInteger bi2 = new BigInteger(Integer.toString(i));
                bi = sum.divide(bi2);
                System.out.println(bi);
            } else {

            }
            cont ++;
        } while (cont <1);


    }
}