#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(n);++i)
#define all(a) (a).begin(),(a).end()
using namespace std;
typedef long long ll;

int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);
  string S;
  cin >> S;
  int k = S.size();
  sort(all(S));
  reverse(all(S));
  swap(S[k-1],S[k-2]);
  if(S[k-1] == S[k-2] || S[0] == '0'){
  	cout << -1 << endl;
  	return 0;
  }
  cout << S << endl;
  return 0;
}