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

  
}

/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