import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long N = scan.nextLong();
		long G = scan.nextLong();
		long V = scan.nextLong();
		scan.close();

		long k = N / 5;
		BigDecimal bdK = new BigDecimal(k);
		BigDecimal b = new BigDecimal(V);
		BigDecimal a = new BigDecimal(G);
		BigDecimal v = a.multiply(bdK);
		BigDecimal v2 = v.divide(b, 15,  BigDecimal.ROUND_HALF_UP);
		System.out.println(v2.toString());


	}
}