import java.util.Scanner;
class YukiCoder02 {

	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 m =(int)N/5;
		double k =m*G ;
		double n =k/V;

		System.out.println(n);

	}

}