import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        long N =sc.nextLong();
        long G =sc.nextLong();
        long V =sc.nextLong();
        double maisu=(int)N/5;
        double x=maisu /V;
        double noudo= x*G;
        System.out.println(noudo);
    }
}