#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
 
using namespace std;
 
typedef long long ll;
 
#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define per(i,a,b) for(ll i=b-1LL;i>=(a);--i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(c) string(1,c)
#define print(x) cout<<#x<<" = "<<x<<endl;
 
#define MOD 1000000007

bool comp(int i, int j) {
    return i > j;
}

int main(){
  string s;
  cin>>s;
  sort(all(s),comp);
  set<string> se;
  do{
    if(s[0]!='0'){
      se.insert(s);
    }
    if(se.sz>=2)break;
  }while(next_permutation(all(s),comp));
  if(se.sz<=1){
    cout << -1 << endl;
  }
  else{
    vector<string> v(all(se));
    cout << v[v.sz-2] << endl;
  }
  return 0;
}