#include <iostream>
using namespace std;

int main(void) {
    string num;
    cin >> num;
    for (int i = 0; i < num.length(); i++) {
        int max = i;
        for (int j = num.length()-1; j > i; j--) {
            if (num[max] < num[j]) {
                max = j;
            }
        }
        if (max != i) {
            char tmp = num[i];
            num[i] = num[max];
            num[max] = tmp;
        }
    }
    cout << num << endl;
    return 0;
}