You are given an integer array nums. You must perform exactly one operation where you can replace one element nums[i] with nums[i] * nums[i]. 

Return the maximum possible subarray sum after exactly one operation. The subarray must be non-empty.

 

Example 1:

Input: nums = [2,-1,-4,-3]

Output: 17

Explanation: You can perform the operation on index 2 (0-indexed) to make nums = [2,-1,16,-3]. Now, the maximum subarray sum is 2 + -1 + 16 = 17.

Example 2:

Input: nums = [1,-1,1,1,-1,-1,1]

Output: 4

Explanation: You can perform the operation on index 1 (0-indexed) to make nums = [1,1,1,1,-1,-1,1]. Now, the maximum subarray sum is 1 + 1 + 1 + 1 = 4.

 

Constraints:

• 1 <= nums.length <= 105
• -104 <= nums[i] <= 104