#include<iostream>
using namespace std;
class Ticket
{
    public:
    double getFinalPrice(string type, double price)
    {
        if(price < 0) 
        return -1;
        if(type == "child")
        price*=0.80;
        else if(type == "senior")
        price*=0.85;
        else if (type == "student")
        price*=0.90;
        return 0;
    }
};
int main()
{
    string type;
    double price;
    cin >> type >> price;
    Ticket t;
    double result = t.getFinalPrice(type,price);
    if(result<0)
    cout<<"Invalid input";
    else
    cout << finalPrice;
    return 0;
}