import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long[] a = new long[3];
        a[0] = in.nextLong(); a[1] = in.nextLong(); a[2] = in.nextLong();
        int k = in.nextInt();
        Arrays.sort(a);
        a[2] = a[2] * (long)Math.pow(2, k);
        System.out.println(a[0] + a[1] + a[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