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.*;
import java.text.*;

public class Main {

    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    long x = sc.nextLong();
    long[] strLen = new long[n+1];
    long cntP = 0;

    public static void main(String[] args){
        new Main().run();
    }

    void run() {

        strLen[0] = 1;
        for (int i=1; i<=n; i++) {
            strLen[i] = strLen[i-1] * 2 + 3;
        }
//        System.out.println(Arrays.toString(strLen));

        while (true) {
            if (x == 1) {
                System.out.println(cntP);
                return;
            }
            if (x == strLen[n] / 2) {
                System.out.println(cntP + (strLen[n]/2 - 1) / 2 + 1 );
                return;
            }
            if (x == strLen[n] / 2 + 1) {
                System.out.println(cntP + (strLen[n]/2 - 1) / 2 + 2 );
                return;
            }
            if (x == strLen[n] - 1) {
                System.out.println(cntP + strLen[n]/2 + 1);
                return;
            }
            if (x == strLen[n]) {
                System.out.println(cntP + strLen[n]/2 + 1);
                return;
            }
            if (1 < x && x < strLen[n] / 2) {
                x--;
                n--;
                continue;
            }
            if (strLen[n] / 2 + 1 < x && x < strLen[n] - 1) {
                cntP += strLen[n] / 4L;
                cntP++;
                x--;
                x -= (strLen[n] / 2 - 1);
                x--;
                n--;
                continue;
            }
        }

    }


}
