import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		String x = sc.next();
		sc.close();

		int[] a = new int[10];
		for (int i = 0; i < x.length(); i++) {
			a[x.charAt(i) - '0']++;
		}

		StringBuilder sb = new StringBuilder();
		for (int i = 9; i >= 0; i--) {
			while (a[i] > 0) {
				sb.append(i);
				a[i]--;
			}
		}

		boolean flg = false;
		for (int i = sb.length() - 1; i > 0; i--) {
			if (sb.charAt(i) != sb.charAt(i - 1)) {
				char ch = sb.charAt(i);
				sb.setCharAt(i, sb.charAt(i - 1));
				sb.setCharAt(i - 1, ch);
				flg = true;
				break;
			}
		}
		if (!flg || sb.charAt(0) == '0') {
			System.out.println(-1);
			return;
		}
		System.out.println(sb.toString());
	}
}