#include <iostream>
#include <string>
#include <math>
using namespace std;
class vehicle{
    protected:
    string type;
    double distance,time;
    public:
    void display(){
        cin>>type>>distance>>time;
        if(type!="Bick"&&type!="car"||distance<0||time<0){
            cout<<"Invalid input";
        }
        else{
            cout<<distance/time;
        }
    }
};
int main(){
vehicle v;
v.display();
return 0;
}