Amr bought a new video game "Guess Your Way Out!". The goal of the game is to find an exit from the maze that looks like a perfect binary tree of height h. The player is initially standing at the root of the tree and the exit from the tree is located at some leaf node. 

Let's index all the leaf nodes from the left to the right from 1 to 2h. The exit is located at some node n where 1 ≤ n ≤ 2h, the player doesn't know where the exit is so he has to guess his way out!

Amr follows simple algorithm to choose the path. Let's consider infinite command string "LRLRLRLRL..." (consisting of alternating characters 'L' and 'R'). Amr sequentially executes the characters of the string using following rules:

  * Character 'L' means "go to the left child of the current node"; 
  * Character 'R' means "go to the right child of the current node"; 
  * If the destination node is already visited, Amr skips current command, otherwise he moves to the destination node; 
  * If Amr skipped two consecutive commands, he goes back to the parent of the current node before executing next command; 
  * If he reached a leaf node that is not the exit, he returns to the parent of the current node; 
  * If he reaches an exit, the game is finished. 



Now Amr wonders, if he follows this algorithm, how many nodes he is going to visit before reaching the exit?

Input

Input consists of two integers h, n (1 ≤ h ≤ 50, 1 ≤ n ≤ 2h).

Output

Output a single integer representing the number of nodes (excluding the exit node) Amr is going to visit before reaching the exit by following this algorithm.

Examples

Input

1 2


Output

2

Input

2 3


Output

5

Input

3 6


Output

10

Input

10 1024


Output

2046

Note

A perfect binary tree of height h is a binary tree consisting of h + 1 levels. Level 0 consists of a single node called root, level h consists of 2h nodes called leaves. Each node that is not a leaf has exactly two children, left and right one. 

Following picture illustrates the sample test number 3. Nodes are labeled according to the order of visit.

<image>
import java.util.*;
import java.math.*;
import java.io.*; 
 public class A{

static FastReader scan=new FastReader();
 public static PrintWriter out = new PrintWriter (new BufferedOutputStream(System.out));
  static LinkedList<Integer>edges[];
  static boolean stdin = true;
    static String filein = "input";
    static String fileout = "output";
static int dx[] = { -1, 0, 1, 0 };
static int dy[] = { 0, 1, 0, -1 };
int dx_8[]={1,1,1,0,0,-1,-1,-1};
int dy_8[]={-1,0,1,-1,1,-1,0,1};
static char sts[]={'U','R','D','L'};
static boolean prime[];
static long LCM(long a,long b){
    return (Math.abs(a*b))/gcd(a,b);
   }
   static long gcd(long a, long b) {
    if(a!=0&&b!=0)
        while((a%=b)!=0&&(b%=a)!=0);
    return a^b;
}
static int countSetBits(int n) 
    { 
        int count = 0; 
        while (n > 0) { 
            count += n & 1; 
            n >>= 1; 
        } 
        return count; 
    } 
 static void sieve(long n) 
    { 
        
        prime = new boolean[(int)n+1]; 
        for(int i=0;i<n;i++) 
            prime[i] = true; 
          
        for(int p = 2; p*p <=n; p++) 
        { 
           
            if(prime[p] == true) 
            { 
                
                for(int i = p*p; i <= n; i += p) 
                    prime[i] = false; 
            } 
        } 
    }  
    
    static int count;
 
  static boolean canTransmit[][]=new boolean[1000+5][1000+5];

    
    
    static boolean vis[];
    static boolean light[][];
    static char grid[][]; 
            
           static boolean isprime(long x)
           {
            for(long i=2;i*i<=x;i++)
                if(x%i==0)
                    return false;
                return true;
           }
           static int perm=0,FOR=0;
           
     

static boolean flag=false;
static int len=100000000;

static ArrayList<Pair>inters=new ArrayList<Pair>();

static ArrayList <Integer>arr;
static boolean can(int n)
{
    ArrayList<Integer>NEW=new ArrayList<Integer>(arr);
for(int i=0;i<arr.size();i++)
{
NEW.set(i,NEW.get(i)+n);
}
Set<Integer>set=new HashSet<Integer>(NEW);
if(set.size()==1)
    return true;
else 
    return false;
}
static StringBuilder sb;
static void swap(int i,int j,StringBuilder st)
{
    char tmp=st.charAt(i);
    st.setCharAt(i,st.charAt(j));
    st.setCharAt(j,tmp);
}
static int n,max;
static int cols[];
static char board[][];
static boolean e(int x,int y)
{
if(x<1||y<0||x>n||y>max)
    return false;
return true;
}
 private static int next(int[] arr, int target)  
    {  
        int start = 0, end = arr.length - 1;  
    
        int ans = -1;  
        while (start <= end) {  
            int mid = (start + end) / 2;  
    
            // Move to right side if target is  
            // greater.  
            if(arr[mid]==target)
                return mid;
            if (arr[mid] <target) {  
                start = mid + 1;  
            }  
    
            // Move left side.  
            else {  
                ans = mid;  
                end = mid - 1;  
            }  
        }  
        return ans;  
    }  
//static boolean vis[][];
    static long solve(int h,long n,int cur)
    {
        if(h==0)
            return 0;
        long half=1L<<(h-1);
        if(n<=half)
        {
            if((cur^1)==0)
                return 1+solve(h-1,n,0);
            else 
                return 2*half+solve(h-1,n,0);
        }
        else 
        {
              if((cur^1)==0)
             return 2*half+solve(h-1,n-half,1);
            else 
                return 1+solve(h-1,n-half,1);
        }
    }
static int dist[][];
public static void main(String[] args)  throws Exception 
{
//SUCK IT UP AND DO IT ALRIGHT
//scan=new FastReader("input.txt");
//out = new PrintWriter ("output.txt");
  int h=scan.nextInt();
  long n=scan.nextLong();
  out.println(solve(h,n,1));
out.close();

//SEE UP 

}
static long binexp(long a,long n)
{
    if(n==0)
        return 1;
    long res=binexp(a,n/2);
    if(n%2==1)
        return res*res*a;
    else 
        return res*res;
}
static long powMod(long base, long exp, long mod) {
       if (base == 0 || base == 1) return base;
       if (exp == 0) return 1;
       if (exp == 1) return base % mod;
       long R = powMod(base, exp/2, mod) % mod;
       R *= R;
       R %= mod;
       if ((exp & 1) == 1) {
           return base * R % mod;
       }
       else return R % mod;
   }
static double dis(double x1,double y1,double x2,double y2)
{
    return Math.sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
}
static long mod(long x,long y)
    {
        if(x<0)
            x=x+(-x/y+1)*y;
        return x%y;
    }
 public static  long pow(long b, long e) {
            long r = 1;
            while (e > 0) {
                if (e % 2 == 1) r = r * b ;
                b = b * b;
                e >>= 1;
            }
            return r;
        }
private static void sort(long[] arr) {
        List<Long> list = new ArrayList<>();
        for (long object : arr) list.add(object);
        Collections.sort(list);
        for (int i = 0; i < list.size(); ++i) arr[i] = list.get(i);
    }
 public static class FastReader {
        BufferedReader br;
        StringTokenizer root;
        
 
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        FastReader(String filename)throws Exception
        {

            br=new BufferedReader(new FileReader(filename));
        }

        boolean hasNext(){
            String line;
            while(root.hasMoreTokens())
                return true;
            return false;
        }
 
        String next() {
            while (root == null || !root.hasMoreTokens()) {
                try {
                    root = new StringTokenizer(br.readLine());
                } catch (Exception addd) {
                    addd.printStackTrace();
                }
            }
            return root.nextToken();
        }
 
        int nextInt() {
            return Integer.parseInt(next());
        }
 
        double nextDouble() {
            return Double.parseDouble(next());
        }
 
        long nextLong() {
            return Long.parseLong(next());
        }
 
        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception addd) {
                addd.printStackTrace();
            }
            return str;
        }
         public int[] nextIntArray(int arraySize) {
            int array[] = new int[arraySize];
 
            for (int i = 0; i < arraySize; i++) {
                array[i] = nextInt();
            }
 
            return array;
        }
}
 static class Pair implements Comparable<Pair>{
        public int x, y;
        public Pair(int x1, int y1) {
            x=x1;
            y=y1;
        }
        @Override
        public int hashCode() {
            return (int)(x + 31 * y);
        }
        public String toString() {
            return x + " " + y;
        }
        @Override
        public boolean equals(Object o){
            if (o == this) return true;
            if (o.getClass() != getClass()) return false;
            Pair t = (Pair)o;
            return t.x == x && t.y == y;
        }
public int compareTo(Pair o)
{
    return (int)(o.x-x);

    }

static class pair{
    int i;
    int j;
pair(int i,int j){
    this.i=i;
    this.j=j;
}}}
 static class tuple{
        int x,y,z;
        tuple(int a,int b,int c){
            x=a;
            y=b;
            z=c;
        }
    }
    static class Edge{
        int d,w;
        Edge(int d,int w)
        {
            this.d=d;
            this.w=w;
        }
    }
}









