#include<iostream>
#include<iomanip>
using namespace std;
int main(){
    string vechicletype;
    double distance,time;
    cin>>vehicle type;
    cin>>distance;
    cin>>time;
    if((vechicletype!="car"&&vechicletype!="bike")||distance<=0||time<=0){
        cout<<"Invalid input";
        return 0;
    }
    double speed=distance/time;
    cout<<fixed<<setprecision(2)<<speed;
    return 0;
}