题解 | #(a+b-c)*d的计算问题#

import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException{
        BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
        String[] nums = read.readLine().split(" ");
        System.out.print((Integer.valueOf(nums[0]) + Integer.valueOf(nums[1])
                         - Integer.valueOf(nums[2])) * Integer.valueOf(nums[3]));
    }
}