Problem Statement

Given is a number sequence A of length N.
Find the sum of squared differences of every pair of elements: $\displaystyle \sum_{i = 2}^{N} \sum_{j = 1}^{i - 1} (A_i - A_j)^2$.

Input

Input is given from Standard Input in the following format:
N
$A_1 A_2 A_3 \cdots A_N$

Output

Print the answer.

Constraints

• $2 \le N \le 3 \times 10^5$
• $|A_i| \le 200$
• All values in input are integers.

Sample Input 1

3
2 8 4

Sample Output 1

56

We have $\sum_{i = 2}^{N} \sum_{j = 1}^{i - 1} (A_i - A_j)^2 = (8 - 2)^2 + (4 - 2) ^ 2 + (4 - 8) ^ 2 = 56$.

Sample Input 2

5
-5 8 9 -4 -3

Sample Output 2

950

见题面 Input 部分

见题面 Output 部分