func_code_string: #include <bits/stdc++.h>   using namespace std;   string s, s2, t1, t2;   int main() {     long long n, l, r, i, j;     cin >> s;     n = s.length();     char mx =  a ;     for (i = n - 1; i >= 0; i--) {       if (s[i] - mx >= 0) {         mx = s[i];         l = i;       }     }     s2 += mx;     r = l;     for (i = mx -  a ; i >= 0; i--) {       char aa =  a  + i;       l = r;       for (j = l + 1; j < n; j++) {         if (s[j] == aa) {           s2 += s[j];           r = j;         }       }     }     cout << s2 << endl;   }   