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.DOWN);
        
        System.out.println(num.multiply(c).divide(v, 12, RoundingMode.HALF_UP));
    }
}