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.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Jaynil
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        DChristmas solver = new DChristmas();
        solver.solve(1, in, out);
        out.close();
    }

    static class DChristmas {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            long x = in.nextLong();
            long ans = 0;
            long t[] = new long[51];
            long p[] = new long[51];
            long b[] = new long[51];
            p[0] = 1;
            t[0] = 1;
            for (int i = 1; i <= 50; i++) {
                p[i] = 2 * p[i - 1] + 1;
                b[i] = 2 * b[i - 1] + 2;
                t[i] = p[i] + b[i];
            }
            boolean patty = true;
            while (n > 0 && x > 0) {
                x--;
                if (x >= t[n - 1]) {
                    if (x >= t[n - 1] + 1) {
                        x -= t[n - 1] + 1;
                        ans += p[n - 1];
                        if (patty) {
                            ans++;
                            patty = false;
                        } else {
                            patty = true;
                        }
                        x++;
                        continue;
                    } else if (x == t[n - 1]) {
                        x -= t[n - 1];
                        ans += p[n - 1];
                        break;
                    }

                } else {
                    n--;
                    patty = true;
                }
            }
            out.println(ans);

        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

    }
}

