At first, let's define function f(x) as follows: $$$ \begin{matrix} f(x) & = & \left\{ \begin{matrix} x/2 & \mbox{if } x  is even \\\ x - 1 & \mbox{otherwise } \end{matrix} \right. \end{matrix} $$$

We can see that if we choose some value v and will apply function f to it, then apply f to f(v), and so on, we'll eventually get 1. Let's write down all values we get in this process in a list and denote this list as path(v). For example, path(1) = [1], path(15) = [15, 14, 7, 6, 3, 2, 1], path(32) = [32, 16, 8, 4, 2, 1].

Let's write all lists path(x) for every x from 1 to n. The question is next: what is the maximum value y such that y is contained in at least k different lists path(x)?

Formally speaking, you need to find maximum y such that \left| \{ x ~|~ 1 ≤ x ≤ n, y ∈ path(x) \} \right| ≥ k.

Input

The first line contains two integers n and k (1 ≤ k ≤ n ≤ 10^{18}).

Output

Print the only integer — the maximum value that is contained in at least k paths.

Examples

Input


11 3


Output


5


Input


11 6


Output


4


Input


20 20


Output


1


Input


14 5


Output


6


Input


1000000 100


Output


31248

Note

In the first example, the answer is 5, since 5 occurs in path(5), path(10) and path(11).

In the second example, the answer is 4, since 4 occurs in path(4), path(5), path(8), path(9), path(10) and path(11).

In the third example n = k, so the answer is 1, since 1 is the only number occuring in all paths for integers from 1 to 20.

import java.io.*;
import java.util.Arrays;
import java.util.Scanner;
import java.util.StringTokenizer;

public class f
{
    public static void print(String str,int val){
        System.out.println(str+"  "+val);
    }

    public long gcd(long a, long b) {
        if (b==0L) return a;
        return gcd(b,a%b);
    }

    public static void debug(long[][] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.println(Arrays.toString(arr[i]));
        }
    }
    public static void debug(int[][] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.println(Arrays.toString(arr[i]));
        }
    }
    public static void debug(String[] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.println(arr[i]);
        }
    }

    public static void print(int[] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.print(arr[i]+" ");
        }
        System.out.print('\n');
    }
    public static void print(String[] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.print(arr[i]+" ");
        }
        System.out.print('\n');
    }
    public static void print(long[] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.print(arr[i]+" ");
        }
        System.out.print('\n');
    }

    static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }
        public FastReader(String path) throws FileNotFoundException {
            br = new BufferedReader(new FileReader(path));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }

    static long k ;
    static long n;
    public static void main(String[] args)
    {
        FastReader s=new FastReader();
        n = s.nextLong();
        k = s.nextLong();
        long odd_end ;
        long even_end;
        if(n%2==0){
            even_end = n/2;
            odd_end = (n-1)/2;
        }
        else {
            even_end = (n-1)/2;
            odd_end = (n-1)/2;
        }
        long start =0;
        long end = even_end;
        while (end-start>1){
            long mid = (start+end)/2;
            if(sum_even(2*mid)){
                start = mid;
            }
            else {
                end = mid-1;
            }
        }
        long max_even  = (sum_even(2*end)?2*end:2*start);
//        System.out.println(start+" "+end);
        start =0;
        end = odd_end;
        while (end-start>1){
            long mid = (start+end)/2;
            if(sum_odd(2*mid+1)){
                start = mid;
            }
            else {
                end = mid-1;
            }
        }
        long max_odd = (sum_odd(2*end+1)?(2*end+1):2*start+1);

//        System.out.println(sum_even(4));

        System.out.println(Math.max(max_even,max_odd));



    }

    static boolean sum_odd(long a){
        if(a==0){
            return false;
        }
        long ans =0;
        long pow = 1;
        while (a<=n){
            if(a+pow-1<=n){
                ans+=pow;
            }
            else {
                ans+=(n+1-a);
            }
            a = a*2;
            pow  = pow*2;
        }
        return (ans>=k);
    }

    static boolean sum_even(long a){
        if(a==0){
            return false;
        }
        long ans =0;
        long pow = 2;
        while (a<=n){
            if(pow+a-1<=n){
                ans+=pow;
            }
            else {
                ans+=(n+1-a);
            }
            a = a*2;
            pow = pow*2;
        }
        return (ans>=k);
    }





//    OutputStream out = new BufferedOutputStream( System.out );
//        for(int i=1;i<n;i++){
//              out.write((arr[i]+" ").getBytes());
//         }
//        out.flush();
//  long start_time = System.currentTimeMillis();
//  long end_time = System.currentTimeMillis();
//  System.out.println((end_time - start_time) + "ms");



}
