Given a **circular array** **C** of integers represented by `A`

, find the maximum possible sum of a non-empty subarray of **C**.

Here, a *circular array* means the end of the array connects to the beginning of the array. (Formally, `C[i] = A[i]`

when `0 <= i < A.length`

, and `C[i+A.length] = C[i]`

when `i >= 0`

.)

Also, a subarray may only include each element of the fixed buffer `A`

at most once. (Formally, for a subarray `C[i], C[i+1], ..., C[j]`

, there does not exist `i <= k1, k2 <= j`

with `k1 % A.length = k2 % A.length`

.)

**Example 1:**

Input:[1,-2,3,-2]Output:3Explanation:Subarray [3] has maximum sum 3

**Example 2:**

Input:[5,-3,5]Output:10Explanation:Subarray [5,5] has maximum sum 5 + 5 = 10

**Example 3:**

Input:[3,-1,2,-1]Output:4Explanation:Subarray [2,-1,3] has maximum sum 2 + (-1) + 3 = 4

**Example 4:**

Input:[3,-2,2,-3]Output:3Explanation:Subarray [3] and [3,-2,2] both have maximum sum 3

**Example 5:**

Input:[-2,-3,-1]Output:-1Explanation:Subarray [-1] has maximum sum -1

**Note: **

`-30000 <= A[i] <= 30000`

`1 <= A.length <= 30000`