Polycarp loves geometric progressions very much. Since he was only three years old, he loves only the progressions of length three. He also has a favorite integer k and a sequence a, consisting of n integers.
He wants to know how many subsequences of length three can be selected from a, so that they form a geometric progression with common ratio k.
A subsequence of length three is a combination of three such indexes i1, i2, i3, that 1 ≤ i1 < i2 < i3 ≤ n. That is, a subsequence of length three are such groups of three elements that are not necessarily consecutive in the sequence, but their indexes are strictly increasing.
A geometric progression with common ratio k is a sequence of numbers of the form b·k0, b·k1, ..., b·kr - 1.
Polycarp is only three years old, so he can not calculate this number himself. Help him to do it.
The first line of the input contains two integers, n and k (1 ≤ n, k ≤ 2·105), showing how many numbers Polycarp's sequence has and his favorite number.
The second line contains n integers a1, a2, ..., an ( - 109 ≤ ai ≤ 109) — elements of the sequence.
Output a single number — the number of ways to choose a subsequence of length three, such that it forms a geometric progression with a common ratio k.
5 2 1 1 2 2 4
4
3 1 1 1 1
1
10 3 1 2 6 2 3 6 9 18 3 9
6
In the first sample test the answer is four, as any of the two 1s can be chosen as the first element, the second element can be any of the 2s, and the third element of the subsequence must be equal to 4.
题目大意：给出一个长度为n的整数序列a和一个数k，要在a中选出长度为3，并满足$b_1\times k^x=b_2,\, b_2\times k^y=b_3$的子序列b。求满足要求的序列的个数。
枚举$b_2$，分别算出它左边有几个数满足可以作为$b_1$，右边有几个数可以作为$b_3$，最后乘起来就行了。
代码在此。
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