题目描述
You are given N points on a plane. Write a program which will find the sum of squares of distances between all pairs of points.
Input
The first line of input contains one integer number N (1 ≤ N ≤ 100 000) — the number of points. Each of the following N lines contain two integer numbers X and Y ( - 10 000 ≤ X, Y ≤ 10 000) — the coordinates of points. Two or more points may coincide.
Output
The only line of output should contain the required sum of squares of distances between all pairs of points.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
4
1 1
-1 -1
1 -1
-1 1
样例输出
32