import java.util.*;


public class Main_yukicoder379 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int g = sc.nextInt();
        int v = sc.nextInt();

        n /= 5;

        System.out.printf("%.13f\n", (double)g * n / v);

        sc.close();
    }
}