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

class Meter {
protected:
    int unitsConsumed;
public:
    void setUnits(int units) {
    unitsConsumed = 50;
    }
};
  
class Bill : public Customer, public Meter {
public:
    void total(int u) {
    int unit = unitsConsumed;
    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.setName(name);
    obj.total(units);
    return 0;
}