import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double n = in.nextInt();
        double g = in.nextInt();
        double v = in.nextInt();

        int goen = (int)n / 5;
        double ans = (goen * g) / v;

        System.out.println(ans);

        in.close();
    }
}