#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(){
    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 ;
    
}