import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

public class Main{
	public static void main(String[] args){
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    Scanner sc = new Scanner(inputStream);
    PrintWriter out = new PrintWriter(outputStream);
    int A = Integer.parseInt(sc.next());
    int B = Integer.parseInt(sc.next());
    int C = Integer.parseInt(sc.next());
    int K = Integer.parseInt(sc.next());
    int max = (int)Math.max(A, Math.max(B, C));
	out.println(A + B + C + max * ((1 << K) - 1));
    out.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