import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        List<Integer> abc = new ArrayList<>();
        abc.add(sc.nextInt());
        abc.add(sc.nextInt());
        abc.add(sc.nextInt());
        Collections.sort(abc);
        int k = sc.nextInt();
        System.out.println((int) (abc.get(0) + abc.get(1) + abc.get(2) * Math.pow(2, k)));
    }

}

/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