// editor1
#include<iostream>
#include<string>
using namespace std;
class customer
{
    public:
    string name;
};
class meter
{
    int unitsconsumed
};
class bill:public customer,public meter
{
    public:
    void cal()
    {
        if(unitsconsumed<0)
        {
            cout<<"Invalid input";
        }
        else
        {
            int total=(unitscondumed*5)+50;
            cout<<" "<<total;
        }
    }
};
int main()
{
    bill b;
    cin>>b.name;
    cin>>b.unitsconsumed;
    b.cal();
    return 0;
}