01. Integer Operations

import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int firstNum = Integer.parseInt(scanner.nextLine()),
            secondNum = Integer.parseInt(scanner.nextLine()),
            thirdNum = Integer.parseInt(scanner.nextLine()),
            fourthNum = Integer.parseInt(scanner.nextLine());

        System.out.println(((firstNum + secondNum) / thirdNum) * fourthNum);
    }
}