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.
N,K=map(int,input().split())

def even(a):
    if a==0:
        return True
    n=2*a
    res=0
    m=n.bit_length()
    M=N.bit_length()
    for i in range(60):
        if i+m<M:
            res+=2**(i+1)
        elif i+m==M:
            if N>>i >n:
                res+=2**i
            elif N>>i ==n:
                res+=N-(n<<i)+1
            if N>>i >n+1:
                res+=2**i
            elif N>>i ==n+1:
                res+=N-((n+1)<<i)+1
            break
    return res>=K

def odd(a):
    n=2*a-1
    res=0
    m=n.bit_length()
    M=N.bit_length()
    for i in range(60):
        if i+m<M:
            res+=2**i
        elif i+m==M:
            if N>>i >n:
                res+=2**i
            elif N>>i ==n:
                res+=N-(n<<i)+1
            break
    return res>=K

start=0
end=10**18
while end-start>1:
    t=(end+start)//2
    if even(t):
        start=t
    else:
        end=t
test1=-1
if even(end):
    test1=2*end
else:
    test1=2*start

start=1
end=10**18
while end-start>1:
    t=(end+start)//2
    if odd(t):
        start=t
    else:
        end=t
test2=-1
if odd(end):
    test2=2*end-1
else:
    test2=2*start-1

print(max(test1,test2))