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

int main() {
  string S;
  cin >> S;
  sort(S.rbegin(), S.rend());
  int s = 0;
  for (int i = S.size() - 1; i >= 0; i--)
    if (S.at(i) != S.back() && !s) swap(S.at(i), S.back()), s = 1;
  cout << ((s && S.front() != '0') ? S : "-1") << "\n";
}