#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
using ll = long long;

int main() {
	string s;
	cin >> s;
	vector<string>a;
	for (int i = 0;i < s.size();i++) {
		for (int j = 0;j < s.size();j++) {
			string t=s;
			swap(t[i], t[j]);
			a.push_back(t);
		}
	}
	sort(a.begin(), a.end());
	cout << a[a.size() - 1] << endl;
}