Bike loves looking for the second maximum element in the sequence. The second maximum element in the sequence of distinct numbers x₁, x₂, ..., x_k (k > 1) is such maximum element x_j, that the following inequality holds: $\text{[math]}$ .

The lucky number of the sequence of distinct positive integers x₁, x₂, ..., 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 s₁, s₂, ..., 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 ≤ 10⁵). The second line contains n distinct integers s₁, s₂, ..., s_n (1 ≤ s_i ≤ 10⁹).

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}.

Maximum Xor Secondary

Examples