04. Vegetable Market

import java.util.Scanner;

public class T13 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        Double P1 = Double.parseDouble(scanner.nextLine());
        Double P2 = Double.parseDouble(scanner.nextLine());
        Double P3 = Double.parseDouble(scanner.nextLine());
        Double P4 = Double.parseDouble(scanner.nextLine());

        Double W1 = (P1 * P3) / 1.94;
        Double W2 = (P2 * P4) / 1.94;
        Double W3 = W1 + W2;
        System.out.printf("%.2f", W3);

    }
}