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, raw_input().split())

p=[1]
a=[1]
for i in range(N):
	p.append( p[-1]*2+1 )
	a.append( a[-1]*2+3 )

#print "p:::",p
#print "a::::",a

X-=1

def f(N,X):
#	print "f (",N ," , ", X ," ) " ,ans

	if X<0:
		return 0		
	elif N==0:
		return 1
	elif X>=a[N]/2:
		X-=(a[N-1]+2)
		return p[N-1]+1+f(N-1,X)
	else:
		X-=1
		return f(N-1,X)

print f(N,X)

