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
N, X = map(int, input().split())
hight, paty = [0]*51, [0]*51
hight[0] = 1
paty[0] = 1

for i in range(1, 51):
	hight[i] = 2*hight[i-1] + 3
	paty[i] = 2*paty[i-1] + 1

def f(n, x):
	if x == 0: return 0
	elif n == 0: return 1

	elif x <= (hight[n-1]+1):
		return f(n-1, x-1)
	else:
		return paty[n-1] + 1 + f(n-1, x-hight[n-1]-2)

print(f(N, X))