Mike wrote the remainder of each number from 1 to n when divided by k. He wants to find how many pairs have equal value, namely how many ordered pairs \((x,y)\) \((1 \le x < y \le n)\) exist such that \(x \equiv y \; (mod \; k)\).

\(\textbf{Input}\)

The first line contains 2 numbers \(n,k\) \((1 \le n,k \le 10^9)\) separated by space.

\(\textbf{Output}\)

Output the number of ordered pairs that satisfy the relation.