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

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] num = new int[3];
		for(int i = 0;i < 3;++i)
			num[i] = sc.nextInt();
		int K = sc.nextInt();
		sc.close();
		
		Arrays.sort(num);
		int ans = num[0] + num[1] + (num[2]<<K);
		System.out.println(ans);
	}
}

/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