import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextInt();
		long m = sc.nextInt();
		sc.close();

		if (n % 2 == 0) {
			System.out.println(n * m);
		} else {
			long v1 = (n - 1) * m;
			long v2 = 1;
			while (v2 <= m) {
				v2 *= 2;
			}
			v2--;
			v2 -= m;
			System.out.println(v1 + v2 * 2);
		}
	}
}