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

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] nums = new int[3];
		for(int i=0;i<3;i++) {
			nums[i]= sc.nextInt();
		}
		int k=sc.nextInt();

		Arrays.sort(nums);
		for(int i=0; i<k;i++) {
			nums[2]*=2;
		}
		System.out.println(nums[0]+nums[1]+nums[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