SP8217 XMAX - XOR Maximization

Given a set of integers $S = \{ a_1, a_2, a_3, \cdots , a_{|S|} \}$, we define a function $X$ on $S$ as follows: $$ X( S ) = a_1 \oplus a_2 \oplus a_3 \oplus \cdots \oplus a_{|S|}. $$ ($\oplus$ stands for bitwise 'XOR' or 'exclusive or') Given a set of $N$ integers, compute the maximum of the $X$-function over all the subsets of the given starting set.

The first line of input contains a single integer $N$, $1 \le N \le 10 ^{5} $. Each of the next $N$ lines contain an integer $a _{i} $, $1 \le a _i \le 10 ^{18} $.

To the first line of output print the solution.