Buggy python submission (verdict: Time Limit Exceeded):
import collections
from decimal import Decimal

n = int(input())
a = [Decimal(input()) for _ in range(n)]
a = [i*10**9 for i in a]
MAX = 19
p_dict = collections.defaultdict(int)

for i in a:
    b_cnt = 0
    while i % 2 == 0 and b_cnt < 18:
        i //= 2
        b_cnt += 1
    f_cnt = 0
    while i % 5 == 0 and f_cnt < 18:
        i //= 5
        f_cnt += 1
    p_dict[(b_cnt, f_cnt)] += 1

ans = 0
for b1, f1 in p_dict:
    for b2, f2 in p_dict:
        if b1+b2 >= 18 and f1+f2 >= 18:
            if b1 == b2 and f1 == f2:
                ans += p_dict[(b1, f1)] * (p_dict[(b2, f2)] - 1)
            else:
                ans += p_dict[(b1, f1)] * p_dict[(b2, f2)]
print(ans//2)

Fixed submission:
import collections
from decimal import Decimal

n = int(input())
a = [Decimal(input()) for _ in range(n)]
a = [int(i*10**9) for i in a]
MAX = 19
p_dict = collections.defaultdict(int)

for i in a:
    b_cnt = 0
    while i % 2 == 0 and b_cnt < 18:
        i //= 2
        b_cnt += 1
    f_cnt = 0
    while i % 5 == 0 and f_cnt < 18:
        i //= 5
        f_cnt += 1
    p_dict[(b_cnt, f_cnt)] += 1

ans = 0
for b1, f1 in p_dict:
    for b2, f2 in p_dict:
        if b1+b2 >= 18 and f1+f2 >= 18:
            if b1 == b2 and f1 == f2:
                ans += p_dict[(b1, f1)] * (p_dict[(b2, f2)] - 1)
            else:
                ans += p_dict[(b1, f1)] * p_dict[(b2, f2)]
print(ans//2)

Buggy python submission (verdict: Time Limit Exceeded):
import collections
from decimal import Decimal

n = int(input())
a = [Decimal(input()) for _ in range(n)]
a = [i*10**9 for i in a]
MAX = 19
p_dict = collections.defaultdict(int)

for i in a:
    b_cnt = 0
    while i % 2 == 0 and b_cnt < 18:
        i //= 2
        b_cnt += 1
    f_cnt = 0
    while i % 5 == 0 and f_cnt < 18:
        i //= 5
        f_cnt += 1
    p_dict[(b_cnt, f_cnt)] += 1

ans = 0
for b1, f1 in p_dict:
    for b2, f2 in p_dict:
        if b1+b2 >= 18 and f1+f2 >= 18:
            if b1 == b2 and f1 == f2:
                ans += p_dict[(b1, f1)] * (p_dict[(b2, f2)] - 1)
            else:
                ans += p_dict[(b1, f1)] * p_dict[(b2, f2)]
print(ans//2)

Fixed submission:
import collections
from decimal import Decimal

n = int(input())
a = [Decimal(input()) for _ in range(n)]
a = [int(i*10**9) for i in a]
MAX = 19
p_dict = collections.defaultdict(int)

for i in a:
    b_cnt = 0
    while i % 2 == 0 and b_cnt < 18:
        i //= 2
        b_cnt += 1
    f_cnt = 0
    while i % 5 == 0 and f_cnt < 18:
        i //= 5
        f_cnt += 1
    p_dict[(b_cnt, f_cnt)] += 1

ans = 0
for b1, f1 in p_dict:
    for b2, f2 in p_dict:
        if b1+b2 >= 18 and f1+f2 >= 18:
            if b1 == b2 and f1 == f2:
                ans += p_dict[(b1, f1)] * (p_dict[(b2, f2)] - 1)
            else:
                ans += p_dict[(b1, f1)] * p_dict[(b2, f2)]
print(ans//2)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = [float(input()) for _ in range(n)]
a = [i*10**9 for i in a]
MAX = 25
p_mat = [[0 for _ in range(MAX)] for _ in range(MAX)]

for i in a:
    b_cnt = 0
    while i % 2 == 0:
        i /= 2
        b_cnt += 1
    f_cnt = 0
    while i % 5 == 0:
        i /= 5
        f_cnt += 1
    p_mat[b_cnt][f_cnt] += 1

ans = 0
for b1 in range(MAX):
    for f1 in range(MAX):
        for b2 in range(MAX):
            for f2 in range(MAX):
                if b1+b2 >= 18 and f1+f2 >= 18:
                    if b1 == b2 and f1 == f2 and p_mat[b1][f1] > 0:
                        ans += p_mat[b1][f1] * (p_mat[b2][f2] - 1)
                    else:
                        ans += p_mat[b1][f1] * p_mat[b2][f2]
print(ans//2)

Fixed submission:
import collections
from decimal import Decimal

n = int(input())
a = [Decimal(input()) for _ in range(n)]
a = [int(i*10**9) for i in a]
MAX = 19
p_dict = collections.defaultdict(int)

for i in a:
    b_cnt = 0
    while i % 2 == 0 and b_cnt < 18:
        i //= 2
        b_cnt += 1
    f_cnt = 0
    while i % 5 == 0 and f_cnt < 18:
        i //= 5
        f_cnt += 1
    p_dict[(b_cnt, f_cnt)] += 1

ans = 0
for b1, f1 in p_dict:
    for b2, f2 in p_dict:
        if b1+b2 >= 18 and f1+f2 >= 18:
            if b1 == b2 and f1 == f2:
                ans += p_dict[(b1, f1)] * (p_dict[(b2, f2)] - 1)
            else:
                ans += p_dict[(b1, f1)] * p_dict[(b2, f2)]
print(ans//2)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = [float(input()) for _ in range(n)]
a = [i*10**9 for i in a]
MAX = 23
p_mat = [[0 for _ in range(MAX)] for _ in range(MAX)]

for i in a:
    b_cnt = 0
    while i % 2 == 0:
        i /= 2
        b_cnt += 1
    f_cnt = 0
    while i % 5 == 0:
        i /= 5
        f_cnt += 1
    p_mat[b_cnt][f_cnt] += 1

ans = 0
for b1 in range(MAX):
    for f1 in range(MAX):
        for b2 in range(MAX):
            for f2 in range(MAX):
                if b1+b2 >= 18 and f1+f2 >= 18:
                    if b1 == b2 and f1 == f2:
                        ans += p_mat[b1][f1] * (p_mat[b2][f2] - 1)
                    else:
                        ans += p_mat[b1][f1] * p_mat[b2][f2]
print(ans//2)

Fixed submission:
import collections
from decimal import Decimal

n = int(input())
a = [Decimal(input()) for _ in range(n)]
a = [int(i*10**9) for i in a]
MAX = 19
p_dict = collections.defaultdict(int)

for i in a:
    b_cnt = 0
    while i % 2 == 0 and b_cnt < 18:
        i //= 2
        b_cnt += 1
    f_cnt = 0
    while i % 5 == 0 and f_cnt < 18:
        i //= 5
        f_cnt += 1
    p_dict[(b_cnt, f_cnt)] += 1

ans = 0
for b1, f1 in p_dict:
    for b2, f2 in p_dict:
        if b1+b2 >= 18 and f1+f2 >= 18:
            if b1 == b2 and f1 == f2:
                ans += p_dict[(b1, f1)] * (p_dict[(b2, f2)] - 1)
            else:
                ans += p_dict[(b1, f1)] * p_dict[(b2, f2)]
print(ans//2)