import java.util.*; import java.math.*; public class Main { private static Scanner sc = new Scanner(System.in); public static void main(String[] args) throws Exception { BigDecimal n = new BigDecimal(sc.nextInt()); BigDecimal c = new BigDecimal(sc.nextInt()); BigDecimal v = new BigDecimal(sc.nextInt()); BigDecimal num = n.divide(new BigDecimal(5), 0, RoundingMode.HALF_UP); System.out.println(num.multiply(c).divide(v, 12, RoundingMode.HALF_UP)); } }