PALIN

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.math.BigInteger;

class PALIN_SPOJ {

    static final BigInteger ZERO = BigInteger.ZERO, ONE = BigInteger.ONE, TEN = BigInteger.TEN;

    public static void main(String[] args) {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BigInteger num = ZERO, copy = ZERO, fh = ZERO, sh = ZERO, newnum = ZERO;
        try{num = new BigInteger(br.readLine());}catch(Exception e){};
        copy = num;

        int c = 0;

        while(copy.compareTo(ZERO) == 1){
            copy = copy.divide(TEN);
            c++;
        }

        copy = num;

        fh = copy.divide(pow(c/2));
        sh = reverse(c%2 == 0? fh: fh.divide(TEN));
        newnum = newnum.add(fh.multiply(pow(c/2)));
        newnum = newnum.add(sh);

        if(newnum.compareTo(num) == -1 || newnum.compareTo(num) == 0 ){
            newnum = ZERO;
            fh = fh.add(ONE);
            sh = reverse(c%2 == 0? fh: fh.divide(TEN));
            newnum = newnum.add(fh.multiply(pow(c/2)));
            newnum = newnum.add(sh);
        }
        System.out.println(newnum);
    }

    private static BigInteger pow(int n) {
        BigInteger ret = ONE;

        for(int i = 1; i <= n; i++)
            ret = ret.multiply(TEN);

        return ret;
    }

    private static BigInteger reverse(BigInteger n) {
        BigInteger ret = ZERO;

        while(n.compareTo(ZERO) == 1){
            ret = ret.multiply(TEN);
            ret = ret.add(n.mod(TEN));
            n = n.divide(TEN);
        }

        return ret;

    }
}