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.Scanner;

class Main{
	static final long MOD = 1000000007;

	static int H, W, K;
	static long[][] dp = new long[110][10];
	static int ans = 0;
	static int n = 0;
	static long x = 0;
	static long[] X;
	static long[] P;




	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);			//文字の入力
		n = sc.nextInt();
		x = sc.nextLong();

		X = new long[51];
		P = new long[51];
		X[0] = 1;
		P[0] = 1;
		for(int i = 1;i <= 50;i++){
			X[i] = 2*X[i-1] + 3;
			P[i] = 2*P[i-1] + 1;
		}
		long ans = sum(n, x);
		System.out.println(ans);






	}

	static long sum(int n,long l){				//lはバーガーのたべる位置
		
		if(n == 1){
			if(l == 1){
				return 0;
				
			}else if(l <= 4){
				return l -1;
			}else{
				return 3;
			}
			
			
		}
		
		if(l <= 1){
			return 0;
		}else  if(l <= 1 + X[n-1]){
			return sum(n-1, l-1);

		}
		else  if(l == 2 + X[n-1]){
			return P[n-1] + 1;
		}

		else  if( l <= 2 + 2*X[n-1]){
			return  P[n-1] + 1 + sum(n-1, l-(2+X[n-1]));
		}
		else {
			return 2*P[n-1] + 1;
		}
		

	}

}







class Pair implements Comparable{
	int from;		//p
	int end;		//y
	int num;
	int bango;
	@Override
	public int compareTo(Object other) {
		Pair otherpair = (Pair)other;

		return end - otherpair.end;
	}
}
