func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long double n, k;     cin >> n >> k;     string s;     cin >> s;     set<string, greater<string> > st;     queue<string> stk;     stk.push(s);     while (k && !stk.empty()) {       string temp = stk.front();       stk.pop();       if (st.find(temp) == st.end()) {         st.insert(temp);         k--;         for (long double i = 0; i < temp.length(); i++) {           string s1 = temp;           s1.erase(s1.begin() + i);           if (s1.size()) stk.push(s1);         }       }     }     long double ans = 0;     if (k == 0 || (k == 1 && stk.empty())) {       for (auto i = st.begin(); i != st.end(); i++) {         ans += (n - (*i).length());       }       if (stk.empty()) ans += n;       cout << ans << endl;     } else {       cout << -1 << endl;     }   }   