BirthdayGift

import java.text.DecimalFormat;
import java.util.Scanner;
import java.lang.Math;

public class Birthday {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int L = Integer.parseInt(scanner.nextLine());
        int W = Integer.parseInt(scanner.nextLine());
        int H = Integer.parseInt(scanner.nextLine());
        double Percentage = Double.parseDouble(scanner.nextLine());
        double Volume = L * W * H;
        double Litre = Volume * 0.001;
        double UsableVolume = Litre * (1 - (Percentage * 0.01));
        DecimalFormat f = new DecimalFormat("##.000");
        System.out.println(f.format(UsableVolume));


    }
}