import java.util.*;

public class Main {
    private static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) throws Exception {
        String s = sc.next();
        int len = s.length();
        int max = Integer.valueOf(s);
        for (int i = 0;i < len;i++) {
            for (int j = i+1;j < len;j++) {
                max = Math.max(max, num(s,i,j));
            }
        }
        System.out.println(max);
    }
    
    private static int num(String s, int i, int j) {
        char[] ary = s.toCharArray();
        char tmp = ary[i];
        ary[i] = ary[j];
        ary[j] = tmp;
        return Integer.valueOf(new String(ary));
    }
}