import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;
 
public class Main {
	public static void main(String[] args){
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
		int c = s.nextInt();

		int k = s.nextInt();

		int coefficient = (int) Math.pow(2, k);

		if(a >= b && a >= c){
			a *= coefficient;
		} else if (a <= b && b >= c){
			b *= coefficient;
		} else if (a <= c && b <= c){
			c *= coefficient;
		}

		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