import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		char[] c = scanner.next().toCharArray();

		for (int i = 0; i < c.length - 1; i++) {
			int max = -1;
			int index = 0;
			for (int j = i; j < c.length; j++) {
				if (max <= c[j]) {
					max = c[j];
					index = j;
				}
			}
			if (c[i] < max) {
				char temp = c[i];
				c[i] = c[index];
				c[index] = temp;
				break;
			}
		}

		System.out.println(String.valueOf(c));
	}

}