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

int main() {
	int num;
	std::cin >> num;

	std::vector<int> v;
	while (num != 0) {
		v.push_back(num % 10);
		num /= 10;
	}

	std::sort(v.begin(), v.end());
	std::reverse(v.begin(), v.end());
	
	for (size_t i = 0; i < v.size(); i++) {
		std::cout << v[i];
	}
	std::cout << std::endl;
	return 0;
}