func_code_string: #include <bits/stdc++.h>   using namespace std;   int cho[30];   char str[1005];   int main() {     int a, b, ans = 0;     cin >> a >> b;     for (int i = 0; i < a; i++) {       cin >> str[i];       cho[str[i] - 96]++;     }     int tot = b;     for (int i = 1; i <= 26; i++) {       if (tot == 0) {         break;       } else if (tot != 0 && cho[i] >= 1) {         if (cho[i - 1] != -1) {           ans += i;           tot--;           cho[i] = -1;         }       }     }     if (tot == 0)       cout << ans << endl;     else if (tot > 0)       cout << -1 << endl;     return 0;   }   