import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] abc= {sc.nextInt(),sc.nextInt(),sc.nextInt()};
		int k=sc.nextInt();
		Arrays.sort(abc);
		for(int i=0; i<k;i++) abc[2] *= 2;
		System.out.println(abc[0]+abc[1]+abc[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