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>

int main()
{
  int N, i, j, count;
  scanf("%d", &N);
  
  float list[N];
  for (i = 0;i < N;i ++) {
    scanf("%f", &list[i]);
  }
  
  int mul_int;
  float mul_float;
  for (i = 0;i < N-1;i ++) {
    for (j = i+1;j < N;j ++) {
      mul_int = list[i] * list[j];
      mul_float = list[i] * list[j];
      if ((mul_int - mul_float) == 0) {
        count ++;
      }
    }
  }
  
  printf("%d", count);
}