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: Time Limit Exceeded)

N, K = map(int, input().split())
ans = 0
if K % 2 != 0:
    M = [a for a in range(0, N+1, K)]
    M.pop(0)
else:
    M = [a for a in range(0, N+1, K//2)]
    M.pop(0)
for a in M:
    for b in M:
        for c in M:
            if ((a+b)%K) == ((b+c)%K) == ((c+a)%K) == 0:
                ans += 1
print(ans)