import java.util.*;
public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[] nums = new int[3];
    for (int i = 0; i < 3; i++) {
      nums[i] = sc.nextInt();
    }
    int K = sc.nextInt();
    Arrays.sort(nums);
    System.out.println(nums[0] + nums[1] + (int) Math.pow(2, K) * nums[2]);
    
  }
}
/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