import java.lang.*;
import java.util.*;


public class Main {

  public static void main(String[] args) {
    Main m = new Main();
    m.exec();
  }

  private void exec() {
    Scanner scan = new Scanner(System.in);
    int a = scan.nextInt();
    int b = scan.nextInt();
    int c = scan.nextInt();
    int k = scan.nextInt();

    int max = a;
    if (b > max) {
      max = b;
    }
    if (c > max) {
      max = c;
    }

    long sum = max * (long)Math.pow(2, k) + a + b + c - max;
    System.out.println(sum);
  }
}
/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