Problem:
Score : 300 points

Problem Statement

You are given N real values A_1, A_2, \ldots, A_N.
Compute the number of pairs of indices (i, j)
such that i < j and the product A_i \cdot A_j is integer.

Constraints

2 \leq N \leq 200\,000

0 < A_i < 10^4

A_i is given with at most 9 digits after the decimal.

Input

Input is given from Standard Input in the following format.

N
A_1
A_2
\vdots
A_N

Output

Print the number of pairs with integer product A_i \cdot A_j (and i < j).

Sample Input 1

5
7.5
2.4
17.000000001
17
16.000000000

Sample Output 1

3

There are 3 pairs with integer product:

7.5 \cdot 2.4 = 18

7.5 \cdot 16 = 120

17 \cdot 16 = 272

Sample Input 2

11
0.9
1
1
1.25
2.30000
5
70
0.000000001
9999.999999999
0.999999999
1.000000001

Sample Output 2

8

Solution in C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using System.Linq;

class Program
{
	static void Main(string[] args)
	{
		int N = int.Parse(Console.ReadLine());
		double[] vs = new double[N]; // double型の配列の宣言
		for (int i = 0; i < N; i++)
		{
			vs[i] = Convert.ToDouble(Console.ReadLine());
		}
		int count = 0;
		int aaa = 0;
		for (int i = 0; i < N - 1; i++)
        {
			for (int a = i + 1; a <= N - 1; a++)
            {
				if ((vs[i] * vs[a]) % 1.000000000000000000 == 0.0000000000000000000) { count++; }
				aaa++;
            }
        }
		Console.WriteLine(count);
		Console.ReadLine();
	}
}
// N = 11  vsのi = 0--11  0::12345678910 1::2345678910