import java.util.Scanner;


public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner scanner = new Scanner(System.in);
		int a = scanner.nextInt();
		int b = scanner.nextInt();
		int c = scanner.nextInt();
		int k = scanner.nextInt();
		if(a >= b && a>=c) {
			a *= (int)Math.pow(2, k);
		}else if(b > a && b >= c) {
			b *= (int)Math.pow(2, k);
		}else {
			c *= (int)Math.pow(2, k);
		}
		
		System.out.println(a+b+c);		
	}

}

/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