import java.util.*;
 class Main{

     public static void main(String []args){
        Scanner scan = new Scanner(System.in);
        ArrayList<Integer> a = new ArrayList<>();
        a.add(scan.nextInt());
        a.add(scan.nextInt());
        a.add(scan.nextInt());
        int n =scan.nextInt();
        int x = Collections.max(a) ;
        for(int i = 0 ; i<n ;i++){
        	x = x*2 ;
        }
       
        
        a.remove(Collections.max(a));
        a.add(x);
        int sum = 0;
        for(Integer u : a){
            sum+=u;
        }
        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