#include<stdio.h>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main() {

	char c[100005];
	int num[10] = {};
	for (int i = 0; i < 100005; i++) c[i] = -1;
	cin >> c;

	for (int i = 0; i < 100000; i++) {
		if (c[i] != -1) {
			num[c[i] - '0']++;
		}
	}

	for (int i = 9; i >= 0; i--) {
		for (int j = 0; j < num[i]; j++) {
			cout << i;
		}
	}
	cout << endl;

	return 0;
}