#include <string>
#include <vector>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;

int keta(long long x){
	int sum=0;
	while(x){
		sum++;	
		x/=10;
	}
	return sum;
}

int main() {
	string x;
	cin >> x;
	sort(x.begin(),x.end());
	
	bool same=true;
	for(int i=0;i<x.size()-1;i++){
		if(x[i]!=x[i+1]){
			same=false;
			break;
		}
	}
	
	if(same){
		cout << -1 << endl;
		return 0;
	}	
		
	vector<int> s;
	do{
		s.push_back(atoi(x.c_str()));
	}while(next_permutation(x.begin(),x.end()));
	
	if(s.size()==1){
		cout << -1 << endl;
		return 0;
	}
	
	if(keta(s[s.size()-2])<keta(s[s.size()-1])){
		cout << -1 << endl;
		return 0;
	}
	
	cout << s[s.size()-2] << endl;
	
	return 0;
}