Given two integers, $\boldsymbol{l}$ and $\textbf{r}$, find the maximal value of $\boldsymbol{a}$ xor $\boldsymbol{b}$, written $a\oplus b$, where $\boldsymbol{a}$ and $\boldsymbol{b}$ satisfy the following condition:

$l\leq a\leq b\leq r$

For example, if $l=11$ and $r=12$, then

$\textbf{11}\oplus11=\textbf{0}$

$\textbf{11}\oplus12=7$

$12\oplus12=0$

Our maximum value is $7$.

Function Description

Complete the maximizingXor function in the editor below. It must return an integer representing the maximum value calculated.

maximizingXor has the following parameter(s):

l: an integer, the lower bound, inclusive
r: an integer, the upper bound, inclusive

Input Format

The first line contains the integer $\boldsymbol{l}$.

The second line contains the integer $\textbf{r}$.

Constraints

$1\leq l\leq r\leq10$^{3}

Output Format

Return the maximal value of the xor operations for all permutations of the integers from $\boldsymbol{l}$ to $\textbf{r}$, inclusive.

Sample Input 0
10
15

Sample Output 0
7

Explanation 0

Here $l=10$ and $r=15$. Testing all pairs:

$10\oplus10=0$

$10\oplus11=1$

$\textbf{10}\oplus12=\textbf{6}$

$\textbf{10}\oplus13=7$

$\textbf{10}\oplus\textbf{14}=4$

$10\oplus15=5$

$\textbf{11}\oplus11=\textbf{0}$

$\textbf{11}\oplus12=7$

$11\oplus13=6$

$11\oplus14=5$

$11\oplus15=4$

$12\oplus12=0$

$12\oplus13=1$

$\textbf{12}\oplus\textbf{14}=2$

$12\oplus15=3$

$13\oplus13=0$

$13\oplus14=3$

$13\oplus15=2$

$14\oplus14=0$

$14\oplus15=1$

$15\oplus15=0$

Two pairs, (10, 13) and (11, 12) have the xor value 7, and this is maximal.

Sample Input 1
11
100

Sample Output 1
127

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