import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String s = scan.next();
		scan.close();
		String []ary = s.split("");
		int max = Integer.parseInt(s);
		for(int i = 0; i < ary.length; i++) {
			for(int j = i + 1; j < ary.length; j++) {
				int t = swap(ary, i, j);
				if(max < t) {
					max = t;
				}
			}
		}
		System.out.println(max);
	}
	public static int swap(String []A, int i, int j) {
		String []B = new String[A.length];
		for(int k = 0; k < A.length; k++) {
			B[k] = A[k];
		}
		String t = B[j];
		B[j] = B[i];
		B[i] = t;
		int a = Integer.parseInt(String.join("", B));
		return a;
	}
}