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 Pascal (FPC 2.6.2) (judge verdict: Wrong Answer)

var
  i,k,n,p,j:longint;
  t,ans:qword;
begin
  readln(n,k);
  for i:=(k div 3) to k do
  for j:=k-(i mod k) to k do
  for p:=(k div 3) to k do
  if ((i+j) mod k=0)and((i+p) mod k=0)and((p+j) mod k=0) then 
  begin
    t:=((n-j) div k+1)*((n-i) div k+1)*((n-p) div k+1);
    ans:=ans+t;
  end;
  writeln(ans);
end.