Description

Albert_s has a multiset S, this question requires you to find a subset T of S that maximizes the expression of T1 xor T2 xor...xor TT ​.

Format

Input

The first line contains the integer $n(1\le n \le 50)$ indicating to the size of S.

The second line contains integer $s1,s2,...,sn(0\le si\le 2^{50})$ indicating the element in S.

Output

Output the maximum value of T1 xor T2 xor...xor TT​.

Samples

4
5 2 8 2

15