## XMAX - XOR Maximization

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Given a set of integers S = { a1, a2, a3, ... a|S| }, we define a function X on S as follows:
X( S ) = a1 ^ a2 ^ a3 ^ ... ^ a|S|.
(^ 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.

### Input

The first line of input contains a single integer N, 1 <= N <= 105.
Each of the next N lines contain an integer ai, 1 <= ai <= 1018.

### Output

To the first line of output print the solution.

### Example

`Input:3124Output:7`

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 < Previous 1 2 3 Next > Aditya Bahuguna: 2014-01-11 23:28:02 awesome problem!! ;) Mojtaba FayazBakhsh: 2013-08-05 06:23:08 nice one! actually same to sgu 275 with a larger n Arpit: 2013-03-21 20:12:45 Please post some more testcases. Trimbitas Petru: 2012-10-15 13:04:33 http://acm.sgu.ru/problem.php?contest=0&problem=275 RE (by Buda IM): This is not same problem, look at constraints here and there Last edit: 2013-01-03 16:40:11 cc: 2011-10-14 15:56:16 is the output for 3 1 2 3 0? manish kapoor: 2011-08-22 15:29:48 sm more test cases pls...

 Added by: gustav Date: 2011-01-26 Time limit: 1s Source limit: 50000B Memory limit: 1536MB Cluster: Cube (Intel G860) Languages: All except: ASM64 Resource: classical problem