CF817B.Makes And The Product

普及/提高-

通过率:0%

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题目描述

After returning from the army Makes received a gift — an array aa consisting of nn 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) ( i<j<k ), such that aiajaka_{i}·a_{j}·a_{k} is minimum possible, are there in the array? Help him with it!

输入格式

The first line of input contains a positive integer number n (3<=n<=105)n (3<=n<=10^{5}) — the number of elements in array aa . The second line contains nn positive integer numbers ai (1<=ai<=109)a_{i} (1<=a_{i}<=10^{9}) — the elements of a given array.

输出格式

Print one number — the quantity of triples (i, j, k)(i, j, k) such that i, ji, j and kk are pairwise distinct and aiajaka_{i}·a_{j}·a_{k} is minimum possible.

输入输出样例

  • 输入#1

    4
    1 1 1 1
    

    输出#1

    4
    
  • 输入#2

    5
    1 3 2 3 4
    

    输出#2

    2
    
  • 输入#3

    6
    1 3 3 1 3 2
    

    输出#3

    1
    

说明/提示

In the first example Makes always chooses three ones out of four, and the number of ways to choose them is 44 .

In the second example a triple of numbers (1,2,3)(1,2,3) is chosen (numbers, not indices). Since there are two ways to choose an element 33 , then the answer is 22 .

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

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