#include <bits/stdc++.h>
#define PI 3.14159265359
#define NIL -1
using namespace std;
const int64_t MOD = 1e9 + 7;

int main() {
	int X;
	cin >> X;

	string S = to_string(X);
	sort(S.begin(), S.end());
	string R = S;
	reverse(R.begin(), R.end());

	if (S.at(0) == S.at(S.size() - 1)) {
		cout << -1 << endl;
		return 0;
	}

	int ans = -1;
	for (int i = stoi(R)-1; i > 0; i--) {
		string s = to_string(i);
		sort(s.begin(), s.end());

		if (s == S) {
			ans = i;
			break;
		}
	}

	cout << ans << endl;
}