func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, h[260], f = 1, c, g, i;   string s;   int main() {     cin >> s >> n;     if (n > s.length()) return cout <<  impossible , 0;     for (i = 0; i < s.length(); i++) h[s[i]]++;     for (i = 97; i <= 122; i++)       if (h[i] > 0) g++;     if (g < n)       c = n - g;     else       f = 1;   l:     if (f == 1)       cout << c;     else       cout <<  impossible ;   }   