#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 flag = 0;
	int f = n[N - 1];
	int si = -1;
	for( int i = N - 2; i >= 0; i-- ) {
		if( n[i] > f ) {
			si = i + 1;
			break;
		}
	}
	if( si > 0 && !( si - 1 == 0 && f == 0 ) ) {
		n[si] = n[si - 1];
		n[si - 1] = f;
		flag = 1;
	}

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