import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner s=new Scanner(System.in);
        String fuel=s.nextLine().toLowerCase();
        if(!s.hasNext()){
            System.out.println("Invalid input");
            return;
        } 
        f quant=s.nextFloat();
        if(!s.hasNextInt()){
            System.out.println("Invalid input");
            return;
        } 
        int  price=s.nextInt();
        
        if(!(fuel.equals("petrol")||fuel.equals0("diesel"))){
            System.out.println("Invalid input");
            return;
        } 
        if(quant<0||quant>100.0||price<0||price>1000){
            System.out.println("Invalid input");
            return;
        } 
        double tot=quant*price;
        System.out.printf("%.2f",tot);
    
    
        
        
        
    }
}