import java.util.*;
public class Main {

	static void solve() {
		Scanner sc = new Scanner(System.in);
		int[] a = {sc.nextInt(),sc.nextInt(),sc.nextInt()};
		int k = sc.nextInt(), t = 0;
		Arrays.sort(a);
		while (k-->0) a[a.length-1]*=2;
		for (int b : a) t+=b;
		System.out.println(t);
		sc.close();			
	}

	public static void main(String args[]) {
		solve();
	}

}
/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