
import java.sql.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;
import java.util.Set;

public class Main {
	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);
		int[] list = new int[3];
		for (int i = 0; i < 3; i++) {
			list[i] = scan.nextInt();
		}
		int k = scan.nextInt();
		Arrays.sort(list);
		
		int ans = (int) (Math.pow(2, k) * list[2]) + list[0] + list[1];
		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