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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

fun main(args: Array<String>) {
    val (n, k) = readLine()!!.split(' ').map(String::toLong)
    var num = 0.5
    if (k % 2L == 0L) {
        while (true) {
            num += 1.0
            if (n < num * k) {
                num -= 1.0
                break
            }
        }
        val ceil = Math.ceil(num)
        val floor = Math.max(Math.floor(num), 1.0)
        println(((ceil * ceil * ceil) + (floor * floor * floor)).toLong())
    } else {
        println((n / k) * (n / k) * (n / k))
    }
}