#include <bits/stdc++.h>
using namespace std;
long long n, k;
long long calc(long long x) {
  long long l = x, r = x, an = 0;
  if (l % 2 == 0) r++;
  while (r <= n) {
    an += (r - l + 1);
    l = l * 2;
    r = r * 2 + 1;
  }
  if (l <= n) an += (n - l + 1);
  return an;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> k;
  long long l = 1, r = n, mi, an = 1;
  if (n == k) {
    cout << 1 << endl;
    return 0;
  } else if (n == k + 1) {
    cout << 2 << endl;
    return 0;
  }
  if (k == 1) {
    cout << n << endl;
    return 0;
  }
  while (l <= r) {
    mi = (l + r) / 2;
    long long x = calc(mi);
    long long y = calc(mi + 1);
    if (x >= k && y >= k) {
      an = max(an, mi + 1);
      l = mi + 2;
    } else if (y >= k) {
      an = max(an, mi + 1);
      l = mi + 2;
    } else if (x >= k) {
      an = max(an, mi);
      l = mi + 1;
    } else
      r = mi - 1;
    mi = (l + r) / 2;
  }
  cout << an << endl;
  return 0;
}

### Prompt

Please formulate a cpp solution to the following problem:

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.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
long long n, k;
long long calc(long long x) {
  long long l = x, r = x, an = 0;
  if (l % 2 == 0) r++;
  while (r <= n) {
    an += (r - l + 1);
    l = l * 2;
    r = r * 2 + 1;
  }
  if (l <= n) an += (n - l + 1);
  return an;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> k;
  long long l = 1, r = n, mi, an = 1;
  if (n == k) {
    cout << 1 << endl;
    return 0;
  } else if (n == k + 1) {
    cout << 2 << endl;
    return 0;
  }
  if (k == 1) {
    cout << n << endl;
    return 0;
  }
  while (l <= r) {
    mi = (l + r) / 2;
    long long x = calc(mi);
    long long y = calc(mi + 1);
    if (x >= k && y >= k) {
      an = max(an, mi + 1);
      l = mi + 2;
    } else if (y >= k) {
      an = max(an, mi + 1);
      l = mi + 2;
    } else if (x >= k) {
      an = max(an, mi);
      l = mi + 1;
    } else
      r = mi - 1;
    mi = (l + r) / 2;
  }
  cout << an << endl;
  return 0;
}

```