Points
说明
E. Points
time limit per test
1 secondmemory limit per test
256 megabytesinput
standard inputoutput
standard outputYou 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≤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.
Output
The only line of output should contain the required sum of squares of distances between all pairs of points.
Examples
Input
4
1 1
-1 -1
1 -1
-1 1
Output
32
样例
