import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    ArrayList<Integer> n = new ArrayList<>();
    for (int i = 0; i < 3; i++) {
      n.add(sc.nextInt());
    }
    int k = sc.nextInt();

    Collections.sort(n);
    for (int i = 0; i < k; i++)
      n.set(2, ((Integer) n.get(2) * 2));
    int ans = 0;
    for (Integer num : n)
      ans += num;
    System.out.println(ans);
  }
}
/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