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.util.*;
import java.io.*;
import java.text.*;

public class E1271 {

	static long n, k;

	public static long getEven(long mid) {
		long lo = mid;
		long hi = mid + 1;
		if (hi > n)
			return 1;
		long sum = 0;
		while (lo <= n) {
			sum += Math.min(hi, n) - lo + 1;
			lo *= 2;
			hi = hi * 2 + 1;
		}
		return sum;
	}

	public static long getOdd(long mid) {
		long lo = mid;
		long hi = mid;
		if (hi > n)
			return 1;
		long sum = 0;
		while (lo <= n) {
			sum += Math.min(hi, n) - lo + 1;
			lo *= 2;
			hi = hi * 2 + 1;
		}
		return sum;
	}

	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		PrintWriter pw = new PrintWriter(System.out);
		n = sc.nextLong();
		k = sc.nextLong();
		long lo = 0;
		long hi = (n - (1 - n % 2) - 1) / 2;
		long ans = 0;
		while (lo <= hi) {
			long mid = lo + hi >> 1;
			if (getOdd(2 * mid + 1) >= k) {
				ans = Math.max(ans, 2 * mid + 1);
				lo = mid + 1;
			} else
				hi = mid - 1;
		}
		lo = 1;
		hi = n / 2;
		while (lo <= hi) {
			long mid = lo + hi >> 1;
			if (getEven(2 * mid) >= k) {
				ans = Math.max(ans, 2 * mid);
				lo = mid + 1;
			} else
				hi = mid - 1;
		}
		pw.println(ans);
		pw.close();

	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public Scanner(FileReader r) {
			br = new BufferedReader(r);
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

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

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

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			String x = next();
			StringBuilder sb = new StringBuilder("0");
			double res = 0, f = 1;
			boolean dec = false, neg = false;
			int start = 0;
			if (x.charAt(0) == '-') {
				neg = true;
				start++;
			}
			for (int i = start; i < x.length(); i++)
				if (x.charAt(i) == '.') {
					res = Long.parseLong(sb.toString());
					sb = new StringBuilder("0");
					dec = true;
				} else {
					sb.append(x.charAt(i));
					if (dec)
						f *= 10;
				}
			res += Long.parseLong(sb.toString()) / f;
			return res * (neg ? -1 : 1);
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

	}
}
