#include <bits/stdc++.h>   using namespace std;   int a[30], col[100100] = {};   int main() {     string s;     cin >> s;     for (int i = 0; i < 26; i++) a[i] = -1;     for (int i = 0; i < s.size(); i++) a[s[i] -  a ] = i;     int p = 25;     for (int i = 0;;) {       while (p >= 0 && a[p] < i) p--;       if (p < 0) break;       int col = 0;       while (i <= a[p]) {         if (s[i] -  a  == p) col++;         i++;       }       for (int j = 0; j < col; j++) cout << s[a[p]];       p--;     }   }   