write a go solution for Description:
Ridhiman challenged Ashish to find the maximum valued subsequence of an array a of size n consisting of positive integers.

The value of a non-empty subsequence of k elements of a is defined as sum2^i over all integers i>=0 such that at least max(1,k-2) elements of the subsequence have the i-th bit set in their binary representation (value x has the i-th bit set in its binary representation if lfloorx/2^irfloormod2 is equal to 1).

Recall that b is a subsequence of a, if b can be obtained by deleting some(possibly zero) elements from a.

Help Ashish find the maximum value he can get by choosing some subsequence of a.

Input Format:
The first line of the input consists of a single integer n (1<=n<=500) — the size of a.

The next line consists of n space-separated integers — the elements of the array (1<=a_i<=10^18).

Output Format:
Print a single integer — the maximum value Ashish can get by choosing some subsequence of a.

Note:
For the first test case, Ashish can pick the subsequence 2,3 of size 2. The binary representation of 2 is 10 and that of 3 is 11. Since max(k-2,1) is equal to 1, the value of the subsequence is 2^0+2^1 (both 2 and 3 have 1-st bit set in their binary representation and 3 has 0-th bit set in its binary representation). Note that he could also pick the subsequence 3 or 2,1,3.

For the second test case, Ashish can pick the subsequence 3,4 with value 7.

For the third test case, Ashish can pick the subsequence 1 with value 1.

For the fourth test case, Ashish can pick the subsequence 7,7 with value 7.. Output only the code with no comments, explanation, or additional text.