#include <bits/stdc++.h>
using namespace std;

int num[1010101];

int main() {
    string s;
    cin >> s;
    for (int i = 0;  i < s.size(); ++i) {
        num[i] = s[i] - '0';
    }
    sort(num, num+s.size());
    for (int i = 0; i < s.size() - 2; ++i) {
        if (num[i] != num[i+1]) {
            swap(num[i], num[i+1]);
            for (int j = s.size()-1; j >= 0; --j) cout << num[j];
            cout << endl;
            return 0;
        }
    }
    cout << -1 << endl;
    return 0;
}