#include<iostream>
using namespace std;
int main() {
int n, nr = 0, c = 9, m;
cin >> n;
while (c >= 0) {
m = n;
while (m != 0 && m % 10 != c)
m /= 10;
if (m != 0)
nr = nr * 10 + m % 10;
c--;
}
cout << nr;
return 0;
