
import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		//		new Main().solveA();
		new Main().solveB();
		// new Main().solveC();
		// new Main().solveD();
	}

	private void solveA() {
		Scanner scanner = null;
		int numA = 0;
		int numB = 0;

		try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();

			int res = numA - 1;
			res += numB >= numA ? 1 : 0;

			System.out.println(res);

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveB() {
		Scanner scanner = null;
		int[] wk = new int[3];
		int numK = 0;

		try {
			scanner = new Scanner(System.in);
			wk[0] = scanner.nextInt();
			wk[1] = scanner.nextInt();
			wk[2] = scanner.nextInt();
			numK = scanner.nextInt();

			Arrays.sort(wk);

			int res = wk[wk.length - 1];
			for (int i = 0; i < numK; i++) {
				res *= 2;
			}
			wk[wk.length - 1] = res;
			res = 0;
			for (int i = 0; i < 3; i++) {
				res += wk[i];
			}

			System.out.println(res);

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveC() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveD() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.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