import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a=sc.nextInt(),b=sc.nextInt(),c=sc.nextInt(),k=sc.nextInt();

		for(int i=0; i<k;i++) {
			if(a>=b) {
				if(a>=c) {
					a*=2;
				}else {
					c*=2;
				}
			}else {
				if(b>=c) {
					b*=2;
				}else {
					c*=2;
				}
			}
		}
		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