import java.util.*;

class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        
        
        List<Long> number = new ArrayList<Long>(){
            {
                add(Long.parseLong(sc.next()));
                add(Long.parseLong(sc.next()));
                add(Long.parseLong(sc.next()));
            }
        };
        
        Collections.sort(number, Comparator.reverseOrder());
        
        long K = Long.parseLong(sc.next());
        
        for(long i=0; i<K; i++){
            number.set(0, number.get(0)*2);
        }
        
        System.out.println(number.get(0) + number.get(1) + number.get(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