#include <iostream>
using namespace std;
class customer{
    
    public :
    void cName(string name){
        cout<<name<<"";
        
    }
};
class Meter{
    public:
    int units(int unit){
        return unit;
        
    }
}:
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(){