Problem:
Score : 300 points

Problem Statement

You are given integers N and K. Find the number of triples (a,b,c) of positive integers not greater than N such that a+b,b+c and c+a are all multiples of K.
The order of a,b,c does matter, and some of them can be the same.

Constraints

1 \leq N,K \leq 2\times 10^5

N and K are integers.

Input

Input is given from Standard Input in the following format:

N K

Output

Print the number of triples (a,b,c) of positive integers not greater than N such that a+b,b+c and c+a are all multiples of K.

Sample Input 1

3 2

Sample Output 1

9

(1,1,1),(1,1,3),(1,3,1),(1,3,3),(2,2,2),(3,1,1),(3,1,3),(3,3,1) and (3,3,3) satisfy the condition.

Sample Input 2

5 3

Sample Output 2

1

Sample Input 3

31415 9265

Sample Output 3

27

Sample Input 4

35897 932

Sample Output 4

114191

Solution in PHP (5.6.30) (judge verdict: Time Limit Exceeded)

<?php
fscanf(STDIN,'%d%d',$N,$K);
$count=0;
for ($a=1; $a <=$N ; $a++) { 
    # code...
    for ($b=1; $b <=$N ; $b++) { 
        # code...
        for ($c=1; $c <=$N ; $c++) { 
            # code...
            $X=$a+$b;
            $Y=$b+$c;
            $Z=$c+$a;
            if($X%$K==0&&$Y%$K==0&&$Z%$K==0){
                $count+=1;
            }
        }
    }
}
echo $count;



?>