import java.util.Scanner;

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

        int n = sc.nextInt();
        int g = sc.nextInt();
        int v = sc.nextInt();
        
        long k = n/5;
        double m = k*g/v ;
        
        System.out.println(m);  
    }
}