31348번 - Geometric Progression 다국어

문제

bobo loves geometric progressions! So he wants to know the number of geometric progressions of length 3ドル$ in a sequence $a_1, a_2, \dots, a_n$.

That is to say, count the number of $(i, j, k)$ where $i < j < k$ and $a_{i} \cdot a_{k} = a_j^2$.

입력

The first line contains an integer $n$ (1ドル \leq n \leq 1000000$).

The second line contains $n$ integers $a_1, a_2, \dots, a_n$ (1ドル \leq a_1 < a_2 < \dots < a_n \leq 1000000$).

출력

A single integer denotes the number of geometric progressions.

제한

힌트