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

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int[] a = new int[3];
		a[0] = sc.nextInt();
		a[1] = sc.nextInt();
		a[2] = sc.nextInt();
		int k = sc.nextInt();
		sc.close();

		Arrays.parallelSort(a);
		for (int i = 0; i < k; i++) {
			a[2] *= 2;
		}
		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