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

public class Main {

	public static void main(String[] args) {

		Scanner s = new Scanner(System.in);

		int[] numArr = new int[3];

		for (int i = 0; i < 3; i++) {
			numArr[i] = s.nextInt();
		}
		int K = s.nextInt();

		Arrays.sort(numArr);

		for (int i = 0; i < K; i++) {
			numArr[2] = numArr[2] * 2;
		}
		System.out.println(numArr[2] + numArr[1] + numArr[0]);
	}

}

/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