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.InputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.util.*;

public class Main {

  public static void main(String[] args) {
    solve(System.in, System.out);
  }

  static void solve(InputStream is, PrintStream os) {
    Scanner sc = new Scanner(is);

    /* read */
    int n = sc.nextInt();

    long burgers[] = new long[51];
    long patties[] = new long[51];

    burgers[0] = 1;
    patties[0] = 1;

    for (int i = 1; i <= 50; i++) {
      burgers[i] = 2 * burgers[i - 1] + 3;
      patties[i] = 2 * patties[i - 1] + 1;
    }

    long x = sc.nextLong();

    os.println(new Burger(n, burgers, patties).eat(x).patty);
  }

  private static class Burger {

    int level;
    long[] burgers;
    long[] patties;

    public Burger(int level, long[] burgers, long[] patties) {
      this.level = level;
      this.burgers = burgers;
      this.patties = patties;
    }


    Eat eat(long toEat) {
      if (level == 0) {
        return new Eat(1L, 1L);
      }

      Eat eat = new Eat(0L, 0L);

      // buns
      eat.add(new Eat(1L, 0L));
      if (toEat - eat.num == 0) {
        return eat;
      }

      // L - 1 burger
      if (burgers[level - 1] <= toEat - eat.num) {
        eat.add(new Eat(burgers[level - 1], patties[level - 1]));
      } else {
        Burger left = new Burger(level - 1, burgers, patties);
        eat.add(left.eat(toEat - eat.num));
      }
      if (toEat - eat.num == 0) {
        return eat;
      }

      // patty
      eat.add(new Eat(1L, 1L));
      if (toEat - eat.num == 0) {
        return eat;
      }

      // L - 1 burger
      if (burgers[level - 1] <= toEat - eat.num) {
        eat.add(new Eat(burgers[level - 1], patties[level - 1]));
      } else {
        Burger right = new Burger(level - 1, burgers, patties);
        eat.add(right.eat(toEat - eat.num));
      }
      if (toEat - eat.num == 0) {
        return eat;
      }

      // buns
      eat.add(new Eat(1L, 0L));

      return eat;
    }

    private static class Eat {

      long num;
      long patty;

      public Eat(long num, long patty) {
        this.num = num;
        this.patty = patty;
      }

      Eat add(Eat other) {
        this.num += other.num;
        this.patty += other.patty;
        return this;
      }
    }

  }

  private static class Scanner {

    private final InputStream is;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;

    Scanner(InputStream is) {
      this.is = is;
    }

    private boolean hasNextByte() {
      if (ptr < buflen) {
        return true;
      } else {
        ptr = 0;
        try {
          buflen = is.read(buffer);
        } catch (IOException e) {
          e.printStackTrace();
        }
        if (buflen <= 0) {
          return false;
        }
      }
      return true;
    }

    private int readByte() {
      if (hasNextByte()) {
        return buffer[ptr++];
      } else {
        return -1;
      }
    }

    private static boolean isPrintableChar(int c) {
      return 33 <= c && c <= 126;
    }

    public boolean hasNext() {
      while (hasNextByte() && !isPrintableChar(buffer[ptr])) {
        ptr++;
      }
      return hasNextByte();
    }

    public String next() {
      if (!hasNext()) {
        throw new NoSuchElementException();
      }
      StringBuilder sb = new StringBuilder();
      int b = readByte();
      while (isPrintableChar(b)) {
        sb.appendCodePoint(b);
        b = readByte();
      }
      return sb.toString();
    }

    public long nextLong() {
      if (!hasNext()) {
        throw new NoSuchElementException();
      }
      long n = 0;
      boolean minus = false;
      int b = readByte();
      if (b == '-') {
        minus = true;
        b = readByte();
      }
      if (b < '0' || '9' < b) {
        throw new NumberFormatException();
      }
      while (true) {
        if ('0' <= b && b <= '9') {
          n *= 10;
          n += b - '0';
        } else if (b == -1 || !isPrintableChar(b)) {
          return minus ? -n : n;
        } else {
          throw new NumberFormatException();
        }
        b = readByte();
      }
    }

    public int nextInt() {
      long nl = nextLong();
      if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) {
        throw new NumberFormatException();
      }
      return (int) nl;
    }

    public double nextDouble() {
      return Double.parseDouble(next());
    }
  }
}
