### BUGGY CODE ###

import sys
import math
import collections
import bisect
import itertools
import decimal

# import numpy as np

sys.setrecursionlimit(10 ** 7)
INF = 10 ** 20
# MOD = 10 ** 9 + 7
MOD = 998244353

ni = lambda: int(sys.stdin.readline().rstrip())
ns = lambda: map(int, sys.stdin.readline().rstrip().split())
na = lambda: list(map(int, sys.stdin.readline().rstrip().split()))
na1 = lambda: list(map(lambda x: int(x) - 1, sys.stdin.readline().rstrip().split()))


# ===CODE===
def prime_factorize(n):
    a = []
    while n % 2 == 0:
        a.append(2)
        n //= 2
    f = 3
    while f * f <= n:
        if n % f == 0:
            a.append(f)
            n //= f
        else:
            f += 2
    if n != 1:
        a.append(n)
    return a


def main():
    n = ni()
    a = [int(decimal.Decimal(input()) * (10 ** 9)) for _ in range(n)]
    res = {}
    border = 18

    for ai in a:
        tmp = prime_factorize(ai)
        c = collections.Counter(tmp)
        two = 0
        five = 0
        if 2 in c.keys():
            two = c[2]
        if 5 in c.keys():
            five = c[5]

        if (two, five) not in res.keys():
            res[(two, five)] = 1
        else:
            res[(two, five)] += 1

    ans = 0
    for k, v in res.items():
        two, five = k
        for tk, tv in res.items():
            t_two, t_five = tk
            if two + t_two >= border and five + t_five >= border:
                if two == t_two and five == t_five:
                    ans += v * (tv - 1)
                else:
                    ans += v * tv

    print(ans // 2)


if __name__ == '__main__':
    main()


### FIXED CODE ###

import sys
import math
import collections
import bisect
import itertools
import decimal

# import numpy as np

sys.setrecursionlimit(10 ** 7)
INF = 10 ** 20
# MOD = 10 ** 9 + 7
MOD = 998244353

ni = lambda: int(sys.stdin.readline().rstrip())
ns = lambda: map(int, sys.stdin.readline().rstrip().split())
na = lambda: list(map(int, sys.stdin.readline().rstrip().split()))
na1 = lambda: list(map(lambda x: int(x) - 1, sys.stdin.readline().rstrip().split()))


# ===CODE===
def prime_factorize(n):
    two = 0
    five = 0
    while n % 2 == 0:
        two += 1
        n //= 2

    while n % 5 == 0:
        five += 1
        n //= 5

    return two, five


def main():
    n = ni()
    a = [int(decimal.Decimal(input()) * (10 ** 9)) for _ in range(n)]
    res = {}
    border = 18

    twoflg = False
    fiveflg = False
    for ai in a:
        two, five = prime_factorize(ai)

        if two >= 9:
            twoflg = True
        if five >= 9:
            fiveflg = True

        if (two, five) not in res.keys():
            res[(two, five)] = 1
        else:
            res[(two, five)] += 1

    ans = 0
    if twoflg and fiveflg:
        for k, v in res.items():
            two, five = k
            for tk, tv in res.items():
                t_two, t_five = tk
                if two + t_two >= border and five + t_five >= border:
                    if two == t_two and five == t_five:
                        ans += v * (tv - 1)
                    else:
                        ans += v * tv

    print(ans // 2)


if __name__ == '__main__':
    main()