In some other world, today is Christmas.

Mr. Takaha decides to make a multi-dimensional burger in his party. A level-L burger (L is an integer greater than or equal to 0) is the following thing:

* A level-0 burger is a patty.
* A level-L burger (L \geq 1) is a bun, a level-(L-1) burger, a patty, another level-(L-1) burger and another bun, stacked vertically in this order from the bottom.



For example, a level-1 burger and a level-2 burger look like `BPPPB` and `BBPPPBPBPPPBB` (rotated 90 degrees), where `B` and `P` stands for a bun and a patty.

The burger Mr. Takaha will make is a level-N burger. Lunlun the Dachshund will eat X layers from the bottom of this burger (a layer is a patty or a bun). How many patties will she eat?

Constraints

* 1 \leq N \leq 50
* 1 \leq X \leq ( the total number of layers in a level-N burger )
* N and X are integers.

Input

Input is given from Standard Input in the following format:


N X


Output

Print the number of patties in the bottom-most X layers from the bottom of a level-N burger.

Examples

Input

2 7


Output

4


Input

1 1


Output

0


Input

50 4321098765432109


Output

2160549382716056
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {
	static long num = 0;
	static long patty = 0;
	static long n = 0;
	static long x = 0;
	static Map<Long,Long> numMap = new HashMap<Long,Long>();
	static Map<Long,Long> pattyMap = new HashMap<Long,Long>();
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		n = sc.nextLong();
		x = sc.nextLong();

		numMap.put(0L,1L);
		pattyMap.put(0L,1L);
		for (long i = 1 ; i <= 50 ; i++) {
			numMap.put(i, numMap.get(i-1)*2+3);
			pattyMap.put(i, pattyMap.get(i-1)*2+1);
		}

		level(n);
		// 出力
		System.out.println(patty);
		sc.close();
	}

	private static boolean level(long lev) {
		if ( (x - num) > numMap.get(lev)) {
			num += numMap.get(lev);
			patty += pattyMap.get(lev);
			return true;
		}

		if (lev == 0) {
			num++;
			patty++;
			if (num == x) return false;
			return true;
		} else {
			num++;
			if (num == x) return false;

			boolean b = level(lev - 1);
			if (b == false) return false;

			num++;
			patty++;
			if (num == x) return false;

			b = level(lev - 1);
			if (b == false) return false;

			num++;
			if (num == x) return false;

			return true;
		}
	}
}
