import java.util.*;

class Main{
	static Scanner s=new Scanner(System.in);
	static int gInt(){
		return Integer.parseInt(s.next());
	}
	public static void main(String[]A){
		long[]a={gInt(),gInt(),gInt()};
		Arrays.sort(a);
		for(int i=gInt();i>0;--i)
			a[2]*=2;
		System.out.println(a[0]+a[1]+a[2]);
	}
}

/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