import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int[] ary = new int[3];
		
		for ( int i = 0; i < 3; i++ ) {
			ary[i] = in.nextInt();
		}
		in.nextLine();
		int k = in.nextInt();
		
		Arrays.sort(ary);
		
		for ( int i = 1; i <= k; i++ ) {
			ary[2] = ary[2]*2;
		}
		
		int fin = 0;
		for ( int i = 0; i < 3; i++ ) {
			fin += ary[i];
		}
		
		System.out.println(fin);
	}
}
/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