#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;

int main(){
    int t, size, ind = 9;
    string s;
    vector<int> v(10);
    cin >> s;
    size = s.size();
    for (int i = 0; i < s.size(); i++){
        t = s[i] - '0';
        v[t]++;
    }
    s = "";
    while (size){
        while (!v[ind]) ind--;
        s += ind + '0';
        v[ind]--;
        size--; 
    }
    cout << s << endl;
}