#include <iostream>
#include <vector>
#include <cstdlib>
#include <algorithm>
#include <functional>
#include <string>
using namespace std;
int main() {
	vector<int> v;
	long long size;
	string str;
	cin >> str;
	size = str.length();
	for (int i = 0; i < size; i++) {
		v.push_back(str[i] - '0');
	}
	sort(v.begin(), v.end(),greater<int>());
	for (int i = 0; i < size; i++) {
		cout << v[i];
	}
	cout << endl;
	return 0;
}