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 (GCC 9.2.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<ctype.h>
#include<stdlib.h>



int main()

{
    int n;
    scanf("%d",&n);
    double num[n];
    for(int i=0;i<n;i++)
    {
        scanf("%lf",&num[i]);
    }

    int count=0;

    for(int i=0;i<n;i++)
    {
        for(int j=i+1;j<n;j++)
        {
            //printf("%.15lf %.15lf\n",ceil(num[i]*num[j]),num[i]*num[j]);
            if((ceil)(num[i]*num[j])-(num[i]*num[j])>0.000000000000001)
            {
                continue;
            }
            count++;
            //printf("upper\n");
        }
    }

    printf("%d\n",count);

    return 0;
}