func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, k;     cin >> n >> k;     string str;     cin >> str;     set<string> visited;     queue<string> s;     s.push(str);     visited.insert(str);     int count = 0, x = 0;     while (!s.empty() && count != k) {       string temp = s.front();       x = x + temp.length();       count++;       s.pop();       for (int i = 0; i < temp.length(); i++) {         string temp2 =   ;         for (int j = 0; j < temp.length(); j++) {           if (j != i) temp2 += temp[j];         }         if (visited.find(temp2) == visited.end()) {           s.push(temp2);           visited.insert(temp2);         }       }     }     if (s.empty() && count < k)       cout <<  -1 ;     else       cout << n * k - x;     return 0;   }   