text: #include <iostream>
  
  using namespace std;
  
  int main() {
      int dogsNum;
      int otherPetsNum;
  
      cin >> dogsNum >> otherPetsNum;
  
      double result = dogsNum * 2.5 + otherPetsNum * 4;
  
      cout.setf(ios::fixed);
      cout.precision(2);
  
      cout << result << " lv." << endl;
  
      return 0;
  }