Problem E

Statement
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Description:
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 Format:
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 Format:
The only line of output should contain the required sum of squares of distances between all pairs of points.

Note:
None