import java.util.*;

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

		// 入力
		Scanner sc = new Scanner(System.in);
		
		// 数値
		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();

		int k = sc.nextInt();
		
		int max = a;
		if (b > max) {
			max = b;
		}
		if (c > max) {
			max = c;
		}
		
		int x = max;
		for (int i = 0; i < k; i++) {
			x = x*2;
		}

		int ans = x + a + b + c - max;

		// 出力
		System.out.println(ans);

		sc.close();

	}
}
/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