import java.io.BufferedReader;
import java.io.InputStreamReader;

public class No039 {

    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(
                    System.in));
            String S = br.readLine();
            int N = Integer.parseInt(S);
            int max = N;
            int Slength = S.length();
            char[] c;
            char tmp;
            int newN = 0;
            for (int j = 0; j < Slength; j++) {

                for (int i = j + 1; i < Slength; i++) {
                    c = S.toCharArray();
                    tmp = c[i];
                    c[i] = c[j];
                    c[j] = tmp;
                    newN = Integer.parseInt(String.copyValueOf(c));
                    max = Math.max(max, newN);
                }
            }
            System.out.println(max);
        } catch (Exception e) {
            System.err.println("Error:" + e.getMessage());
        }
    }

}