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 Python (3.4.3) (judge verdict: Wrong Answer)

N, K = map(int,input().split())
ans = 0

ev = 0
ev2 = 0
od = 0
if K % 2 == 1:
    for i in range(N):
        if i % K == 0:
            od += 1

    print(od**3)
else:
    for i in range(N):
        if i % K == 0:
            ev += 1
        if i % (K/2) == 0:
            ev2 += 1
        if i % K == 0 and i % (K/2) == 0:
            od += 1
    ans = ev**3 + ev2**3
    print(ans)