#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

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

	vector<char> charList(N.length());
	for (int i = 0; i < N.length(); ++i) {
		charList[i] = N[i];
	}

	sort(charList.rbegin(), charList.rend());

	for (int i = 0; i < N.length(); ++i) {
		cout << charList[i];
	}

	cout << endl;

	getchar();
	getchar();
}