M is alone and he has an array $a_1, a_2, ..., a_n$. M wants to choose two integers $i, j$ such that $i \neq j, 1 \leq i, j \leq n$ and the value $a_i \& a_j$(bitwise AND) is maximum.

What is the maximum value M can get?

Input

First line contains only $n$, legnth of array.

Second line contains the array elements $a_1, a_2, ..., a_n$separated by space.

$1 \leq n \leq 3 \times 10^5$

$1 \leq a_i \leq 10^9$

Output

The only line of output contains an integer, maximum value value that M can get.