Problem Statement

Given are $N integers A_1,\ldots,A_N$.
Find the sum of |A_i-A_j| over all pairs i,j such that $1\leq i < j \leq N$.
In other words, find $\displaystyle{\sum_{i=1}^{N-1}\sum_{j=i+1}^{N} |A_i-A_j|}$.

Input

Input is given from Standard Input in the following format:
N
$A_1 \ldots A_N$

Output

Print the answer.

Constraints

• $2 \leq N \leq 2 \times 10^5$
• $|A_i|\leq 10^8$
• A_i is an integer.

Sample Input 1

3
5 1 2

Sample Output 1

8

We have |5-1|+|5-2|+|1-2|=8.

Sample Input 2

5
31 41 59 26 53

Sample Output 2

176

见题面 Input 部分

见题面 Output 部分