#include<iostream>
#include<string>
using namespace std;
class Customer {
    protected:
      std::string name;
    public:
      void setName(const std::string& customerName) {
          name = customerName;
      }
};

  class Meter {
     protected:
       int unitsConsumed;
     public:
    void setUnits(int units) {
        unitsConsumed = units;
    }
  };
  
   class Bill : public Customer, public Meter {
       public:
       void total( int u); {
           int unit = units(u);
           int t = unit*5 + 50;
           cout << t << endl;
       }
   };
   
   int main() {
       string name;
       int units;
       cin >> name >> units;
       if(units < 0) {
           cout << "Invalid input";
           return 0;
       }
       Bill obj;
       obj.cName(name);
       obj.total(units);
       return 0;
   }