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.*;

public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    long n = scan.nextLong();
    long x = scan.nextLong();

    long sum = 0;
    long start = 1;
    long end = find1(n);

    while (n >= 1){
      long mid = (long) (start+end)/2;
      if (x == start){
        break;
      }

      if (x == end){
        sum += 2*find2(n-1);
        sum += 1;
        break;
      }

      if (n == 1){
        sum += x-start;
        break;
      }

      if (x == mid){
        sum += 1;
        long add = find2(n-1);
        sum += add;
        System.out.println(sum);
        return;
      }

      if (x > mid){
        sum += 1;
        long add = find2(n-1);
        sum += add;
        start = mid+1;
        end -= 1;
      }
      else{
        end = mid-1;
        start += 1;
      }
      n -= 1;
    }
    System.out.println(sum);
  }

  static long find1(long n){
    long ret = 1;
    long base = 2;
    n += 2;
    while (n > 0){
      if ((n & 1) == 1){
        ret *= base;
      }
      base = base*base;
      n >>= 1;
    }
    ret -= 3;
    return ret;
  }

  static long find2(long n){
    long ret = 1;
    long base = 2;
    n += 1;
    while (n > 0){
      if ((n & 1) == 1){
        ret *= base;
      }
      base = base*base;
      n >>= 1;
    }
    ret -= 1;
    return ret;
  }
}
