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

int main() {
	char cs[20];
	cin >> cs;
	int N = strlen(cs);
	for (int i = 0; i < N; i++)
	{
		int max = cs[i];
		int pos = i;
		for (int j = N - 1; j >= i + 1; j--)
		{
			if (max < cs[j]){
				max = cs[j];
				pos = j;
			}
		}
		if (pos != i){
			swap(cs[i], cs[pos]);
			break;
		}
	}
	cout << cs << endl;
}