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())
p, q = [1] + [0] * n, [1] + [0] * n

for i in range(1, n+1):
    p[i] = p[i-1] * 2 + 1
    q[i] = q[i-1] * 2 + 3    

def rec(i, x):
    if i == 0: return 1 if x >= 1 else 0
    mid = q[i-1] + 2
    if x < mid:
        return rec(i-1, x-1)
    else:
        return p[i-1] + 1 + rec(i-1, x-mid)

print(rec(n, x))
