import java.util.*;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int A = sc.nextInt();
		int B = sc.nextInt();
		int C = sc.nextInt();
		int K = sc.nextInt();
		int max;
		if(A < B) {
			max = A;
			A = B;
			B = max;
		}
		if(A < C) {
			max = A;
			A = C;
			C = max;
		}
		for(int i = 0;i < K;i++) {
			A = A * 2;
		}
		System.out.println(A+B+C);
		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