Triangle Counting#8616
You are given rods with lengths 1, 2, \dots, n. You may choose any three of them to form a triangle. How many distinct triangles can be formed? Two triangles are considered different if there exists at least one pair of corresponding sides with different lengths.
Each line contains one integer n~(3 \le n \le 10^6). The last line contains a value n < 3 and should not be processed.
For each test case, print on a separate line the number of distinct triangles that can be formed.
Example 1