import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int[] numbers = new int[3];
        numbers[0] = in.nextInt();
        numbers[1] = in.nextInt();
        numbers[2] = in.nextInt();
        Arrays.sort(numbers);
        System.out.println((int) Math.pow(2, in.nextInt()) * numbers[2] + numbers[0] + numbers[1]);
        in.close();
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz