import java.util.*;


public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int k = sc.nextInt();
    int answer=0;
    int max=a;
    int other1=b;
    int other2=c;
    if(b>max){
      max=b;
      other1=a;
      other2=c;
    }
    if(c>max){
      max=c;
      other1=a;
      other2=b;
    }
    for(int i=0;i<k;i++){
      max *= 2;
    }
    System.out.print(max+other1+other2);
  }
}

/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