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 PyPy3 (7.3.0) (judge verdict: Time Limit Exceeded)

# coding: utf-8
# Your code here!
import sys
readline = sys.stdin.readline
read = sys.stdin.read

#n,*a = [int(i) for i in read().split()]
n = int(readline())
#a = []
C = [0]*n
D = [0]*n

M = 10**9
for i in range(n):
    bi = float(readline())
    ai = int(round(bi*M))
        
    c2=c5=0    
    x = ai
    while x%2==0:
        c2 += 1
        x//=2
    
    x = ai
    while x%5==0:
        c5 += 1
        x//=5
    #print(ai,c2,c5)
    #a.append((c2,c5,v))
    C[i] = c2
    D[i] = c5
    #print(ai)
#print(C)
#print(D)

ans = 0
for i in range(n):
    for j in range(i+1,n):
        if C[i]+C[j] >= 18 and D[i]+D[j] >= 18:
            ans += 1

print(ans)