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

int main()
{
	string S;
	cin >> S;

	int N = S.size();
	vector<int> n( N );
	for( int i = 0; i < N; i++ ) {
		n[i] = S[i] - '0';
	}
	sort( n.begin(), n.end(), greater<int>() );
	int s = n[N - 1];
	int flag = 0;
	for( int i = N - 2; i >= 0; i-- ) {
		if( n[i] > s ) {
			if( i == 0 && s == 0 ) break;
			n[N - 1] = n[i];
			n[i] = s;
			flag = 1;
			break;
		}
	}

	if( flag == 0 ) cout << -1 << endl;
	else {
		for( int i = 0; i < N; i++ ) {
			char c = (char)(n[i] + '0');
			cout << c;
		}
		cout << endl;
	}
}