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.