#include<iostream>
#include<string>
#include <vector>
#include <algorithm>
int main()
{
	std::string s;
	std::cin >> s;

	std::vector<int> v;
	for (const char c : s)
	{
		v.push_back(c - '0');
	}
	std::sort(v.begin(), v.end(), [](int x, int y) -> int { return (x > y); });

	for (auto i : v)
	{
		std::cout << i;
	}
	std::cout << std::endl;
}