CF817B.Makes And The Product

After returning from the army Makes received a gift — an array a consisting of n positive integer numbers. He hadn't been solving problems for a long time, so he became interested to answer a particular question: how many triples of indices (i,  j,  k) (i < j < k), such that a__i·a__j·a__k is minimum possible, are there in the array? Help him with it!

从部队归来后，马克收到了一份礼物——一个由 $n$ 个正整数组成的数组 $a$。他已许久未解题，因此对一个特定问题产生了兴趣：数组中满足 $i < j < k$ 且乘积 $a_i \cdot a_j \cdot a_k$ 达到最小可能值的三元组索引 $(i, j, k)$ 共有多少个？请帮他解决这个问题！

The first line of input contains a positive integer number n (3 ≤ n ≤ 105) — the number of elements in array a. The second line contains n positive integer numbers a__i (1 ≤ a__i ≤ 109) — the elements of a given array.

输入的第一行包含一个正整数 $n$（$3 \leq n \leq 10^5$）—— 数组 $a$ 的元素个数。
第二行包含 $n$ 个正整数 $a_i$（$1 \leq a_i \leq 10^9$）—— 给定数组的元素。

Print one number — the quantity of triples (i,  j,  k) such that i,  j and k are pairwise distinct and a__i·a__j·a__k is minimum possible.

输出一个数字——满足条件的三元组 $(i, j, k)$ 的个数，其中 $i$、$j$、$k$ 两两不同，且 $a_i \cdot a_j \cdot a_k$ 取得最小可能值。

In the first example Makes always chooses three ones out of four, and the number of ways to choose them is 4.

In the second example a triple of numbers (1, 2, 3) is chosen (numbers, not indices). Since there are two ways to choose an element 3, then the answer is 2.

In the third example a triple of numbers (1, 1, 2) is chosen, and there's only one way to choose indices.

在第一个例子中，Makes 总是从四个数中选择三个 1，选择的方式数为 4。

在第二个例子中，选择的是数字三元组 (1, 2, 3)（注意是数值，而非下标）。由于元素 3 有两种选择方式，因此答案为 2。

在第三个例子中，选择的是数字三元组 (1, 1, 2)，而选择下标的方式仅有一种。