import java.util.*;

public class Main{

    public static void main(String[] args){
        
        Scanner scan = new Scanner(System.in);

        int a,b,c,k,max,max_;
        a = Integer.parseInt(scan.next());   
        b = Integer.parseInt(scan.next());
        c = Integer.parseInt(scan.next());
        k = Integer.parseInt(scan.next());
        max = Math.max(a,b);
        max = Math.max(max,c);
        max_ = max;
        for(int i = 0;i < k;i++){
            max = max*2;
        }
        int ans;
        ans = max + a + b + c - max_;

        System.out.println(ans);
    }
}
/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