import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String line = sc.nextLine();
        String[] lineArray = line.split(" ");

        long n = Long.parseLong(lineArray[0]);
        long g = Long.parseLong(lineArray[1]);
        long v = Long.parseLong(lineArray[2]);
        
        long k = n/5;
        double m = k*g/v ;
        
        System.out.println(m);  
    }
}