import java.util.Scanner;
 
public class Main {
 
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int k = sc.nextInt();
        
        int max = 0;
        if (Math.max(a, b) == a && Math.max(a, c) == a) {
        	max = a;
        	a = 0;
        } else if (Math.max(a, b) == b && Math.max(b, c) == b) {
        	max = b;
        	b = 0;
        } else {
        	max = c;
        	c = 0;
        }
        
        long newK = (long) Math.pow(2,k);
        
        
        System.out.println(a + b + c + (max * newK));
    }
    
}
/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