#include<iostream>
using namespace std;
class customer{
    public :
    void setname(string name){
        cout<<name<<" ";
        
    }
};
class meter{
    public:
    int unit(int unit){
        return unit;
    }
};
class bill: public customer,public meter{
    public:
    void total(int u){
        int unit = unit (u);
        int t = unit*5 + 50;
        cout<<t<<endl;
        
    }
};
int main ()
{
    string name ;
    int units;
    cin>>name>>unit;
    if(unit<0){
        cout<<"invalid inputs";
        return 0;
    }
    bill obj;
    obj.name(names);
    obj.total(unit);
    return 0;
}