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≤x<y≤n) exist such that x≡y(modk).
Input
The first line contains 2 numbers n,k (1≤n,k≤109) separated by space.
Output
Output the number of ordered pairs that satisfy the relation.
The pairs are : (2,4),(1,3),(1,5),(3,5).