Matcom Online Grader
Faculty of Mathematics and Computer Science of University of Havana

You are given $n$ rods of length $1, 2, ..., n$. You have to pick any $3$ of them and build a triangle. How many distinct triangles can you make? Note that, two triangles will be considered different if they have at least $1$ pair of arms with different length.

Input

The input for each case will have only a single positive integer  $n$ $(3 \le n \le 1000000)$. The end of input will be indicated by a case with $n < 3$. This case should not be processed.

Output

For each test case, print the number of distinct triangles you can make.

Sample test(s)