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.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.StringTokenizer;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author xylenox
 */
public class e {
    public static void main(String[] args) {
        FS in = new FS(System.in);
        PrintWriter out = new PrintWriter(System.out);
        long n = in.nextLong();
        long k = in.nextLong();
        
        long odd = 1;
        for(int pow = 60; pow > 0; pow--) {
            long tmp = odd+(1l<<pow);
            if(num(tmp, n) >= k) odd = tmp;
        }
        
        long even = 0;
        for(int pow = 60; pow > 0; pow--) {
            long tmp = even+(1l<<pow);
            if(num(tmp, n) >= k) even = tmp;
        }
        
        System.out.println(Math.max(odd, even));
        out.close();
    }
    
    static long num(long x, long n) {
        long res = 0;
        long num = 1;
        if(x%2 == 0) num = 2;
        while(x <= n) {
            res += Math.min(n-x+1, num);
            num *= 2;
            x *= 2;
        }
        return res;
    }
    
    static class FS {
        BufferedReader in;
        StringTokenizer token;
        
        public FS(InputStream st) {
            in = new BufferedReader(new InputStreamReader(st));
        }
        
        public String next() {
            if(token == null || !token.hasMoreElements()) {
                try {
                    token = new StringTokenizer(in.readLine());
                } catch(Exception e) {}
                return next();
            }
            return token.nextToken();
        }
        
        public int nextInt() {
            return Integer.parseInt(next());
        }
        
        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}
