import java.util.*; import java.math.*; public class Main { static Scanner sc = new Scanner(System.in); public static void main(String[] args) { long n = sc.nextLong(); long g = sc.nextLong(); long v = sc.nextLong(); long total = n/5*g; BigDecimal b1 = new BigDecimal(total); BigDecimal b2 = new BigDecimal(v); BigDecimal ans = b1.divide(b2,9,RoundingMode.HALF_UP); System.out.println(ans); } }