CF76E.Points

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.

The first line of input contains one integer number $N$ ( $1<=N<=100000$ ) — the number of points. Each of the following $N$ lines contain two integer numbers $X$ and $Y$ ( $-10000<=X,Y<=10000$ ) — the coordinates of points. Two or more points may coincide.

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