Since Grisha behaved well last year, at New Year's Eve he was visited by Ded Moroz who brought an enormous bag of gifts with him! The bag contains $*n*$ sweet candies from the good ol' bakery, each labeled from $1$ to $*n*$ corresponding to its tastiness. No two candies have the same tastiness.

The choice of candies has a direct effect on Grisha's happiness. One can assume that he should take the tastiest ones — but no, the holiday magic turns things upside down. It is the xor-sum of tastinesses that matters, not the ordinary sum!

A xor-sum of a sequence of integers $*a*_{1}, *a*_{2}, ..., *a*_{*m*}$ is defined as the bitwise XOR of all its elements: , here denotes the bitwise XOR operation; more about bitwise XOR can be found here.

Ded Moroz warned Grisha he has more houses to visit, so Grisha can take no more than $*k*$ candies from the bag. Help Grisha determine the largest xor-sum (largest xor-sum means maximum happiness!) he can obtain.

Input

The sole string contains two integers $*n*$ and $*k*$ ($1 ≤ *k* ≤ *n* ≤ 10^{18}$).

Output

Output one number — the largest possible xor-sum.

Note

In the first sample case, one optimal answer is $1$, $2$ and $4$, giving the xor-sum of $7$.

In the second sample case, one can, for example, take all six candies and obtain the xor-sum of $7$.