Description

Given $N$ integers $A_1, A_2, ..., A_N$, select two of them to perform an XOR operation. What is the maximum possible result?

Input Format

The first line contains an integer $N$.

The second line contains $N$ integers $A_i$.

Output Format

Output a single integer representing the answer.

Sample 1

5
2 9 5 7 0

14

Constraints & Hints

For $100\%$ of the data, $1\le N\le 10^5$ and $0\le A_i <2^{31}$.