Bike loves looking for the second maximum element in the sequence. The second maximum element in the sequence of distinct numbers $*x*_{1}, *x*_{2}, ..., *x*_{*k*}$ $(*k* > 1)$ is such maximum element $*x*_{*j*}$, that the following inequality holds: .

The lucky number of the sequence of distinct positive integers $*x*_{1}, *x*_{2}, ..., *x*_{*k*}$ $(*k* > 1)$ is the number that is equal to the bitwise excluding OR of the maximum element of the sequence and the second maximum element of the sequence.

You've got a sequence of distinct positive integers $*s*_{1}, *s*_{2}, ..., *s*_{*n*}$ $(*n* > 1)$. Let's denote sequence $*s*_{*l*}, *s*_{*l* + 1}, ..., *s*_{*r*}$ as $*s*[*l*..*r*]$ $(1 ≤ *l* < *r* ≤ *n*)$. Your task is to find the maximum number among all lucky numbers of sequences $*s*[*l*..*r*]$.

Note that as all numbers in sequence $*s*$ are distinct, all the given definitions make sence.

Input

The first line contains integer $*n*$ $(1 < *n* ≤ 10^{5})$. The second line contains $*n*$ distinct integers $*s*_{1}, *s*_{2}, ..., *s*_{*n*}$ $(1 ≤ *s*_{*i*} ≤ 10^{9})$.

Output

Print a single integer — the maximum lucky number among all lucky numbers of sequences $*s*[*l*..*r*]$.

Note

For the first sample you can choose $*s*[4..5] = {4, 3}$ and its lucky number is $(4 *xor* 3) = 7$. You can also choose $*s*[1..2]$.

For the second sample you must choose $*s*[2..5] = {8, 3, 5, 7}$.