import java.util.Scanner;

public class Main {
	static boolean memo[];
	static int ans, min;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		char[] n = sc.next().toCharArray();
		char tmp;
		int idx;
		for (int i = 0; i < n.length - 1; i++) {
			tmp = '0';
			idx = 0;
			for (int j = n.length - 1; j > i; j--) {
				if (n[i] < n[j]) {
					if (tmp < n[j]) {
						tmp = n[j];
						idx = j;
					}
				}
			}
			if (tmp != '0') {
				n[idx] = n[i];
				n[i] = tmp;
				break;
			}
		}
		for (int i = 0; i < n.length; i++) {
			sb.append(n[i]);
		}
		System.out.println(sb);
	}
}