write a go solution for Description:
Lunar New Year is approaching, and Bob is struggling with his homework – a number division problem.

There are n positive integers a_1,a_2,ldots,a_n on Bob's homework paper, where n is always an even number. Bob is asked to divide those numbers into groups, where each group must contain at least 2 numbers. Suppose the numbers are divided into m groups, and the sum of the numbers in the j-th group is s_j. Bob's aim is to minimize the sum of the square of s_j, that is \sum_{j = 1}^{m} s_j^2.

Bob is puzzled by this hard problem. Could you please help him solve it?

Input Format:
The first line contains an even integer n (2<=n<=3*10^5), denoting that there are n integers on Bob's homework paper.

The second line contains n integers a_1,a_2,ldots,a_n (1<=a_i<=10^4), describing the numbers you need to deal with.

Output Format:
A single line containing one integer, denoting the minimum of the sum of the square of s_j, which is \sum_{i = j}^{m} s_j^2, where m is the number of groups.

Note:
In the first sample, one of the optimal solutions is to divide those 4 numbers into 2 groups 2,8,5,3. Thus the answer is (2+8)^2+(5+3)^2=164.

In the second sample, one of the optimal solutions is to divide those 6 numbers into 3 groups 1,2,1,2,1,2. Thus the answer is (1+2)^2+(1+2)^2+(1+2)^2=27.. Output only the code with no comments, explanation, or additional text.