import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        // long startTime = System.currentTimeMillis();

        Scanner scanner = new Scanner(System.in);

        long[] n = new long[3];
        n[0] = scanner.nextInt();
        n[1] = scanner.nextInt();
        n[2] = scanner.nextInt();
        int k = scanner.nextInt();
        scanner.close();

        int maxIdx = 0;
        if (n[maxIdx] < n[1]) {
            maxIdx = 1;
        }
        if (n[maxIdx] < n[2]) {
            maxIdx = 2;
        }

        // System.out.println(maxIdx);

        long d = (long) Math.pow(2, k);

        long result = 0;

        for (int i = 0; i < 3; i++) {
            result += (i == maxIdx) ? (n[i] * d) : n[i];
        }

        System.out.println(result);

        // System.out.println(System.currentTimeMillis() - startTime);
    }
}
/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