#include <iostream>
#include <vector>
#include <deque>
#include <algorithm>
#include <numeric>
#include <string>
#include <cstring>
#include <list>
#include <unordered_set>
#include <tuple>
#include <cmath>
#include <limits>
#include <type_traits>
#include <iomanip>
#include <map>
#include <unordered_map>
#include <queue>
#include <stack>
#include <set>
#include <bitset>
#include <complex>
#include <regex>
#include <random>
using namespace std;

#define rep(i,n)	for(lint i = 0; i < n; i++)
#define repr(i,n)	for(lint i = n - 1; i >= 0; i--)
#define repi(i,ini,n)	for(lint i = ini; i < n; i++)
#define repir(i,ini,n)	for(lint i = n-1; i >= ini; i--)
#define repb(i,start,end)	for(lint i = start; i <= end; i++)
#define repbr(i,start,end)	for(lint i = end; i >= start; i--)

#define bit(n)				(1LL << (n))

#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define rg(v, ini, end) v.begin() + ini, v.begin()+end

#define ret return 0;
#define chmax(a, b) a=max(a,b)
#define chmin(a, b) a=min(a,b)

using lint = long long;
using ulint = unsigned long long;
using ld = long double;
struct xy
{
	lint x, y;
	xy() :x(0), y(0) {}
	xy(lint _x, lint _y) : x(_x), y(_y) {}
	xy operator+(const xy& p) const
	{
		return xy(x + p.x, y + p.y);
	}
	bool operator<(xy p) const
	{
		if (y == p.y)
			return x < p.x;
		return y < p.y;
	}
};
struct xyd
{
	ld x, y;
	xyd() :x(0), y(0) {}
	xyd(long double _x, long double _y) : x(_x), y(_y) {}
};
using vec = vector<lint>;
using vecd = vector<ld>;
using vecs = vector<string>;
using vecp = vector<xy>;
template<class T> using vect = vector<T>;
class vec2 : public vector<vector<lint>>
{
public:
	vec2() {}
	vec2(lint n) : vector(n) {}
	vec2(lint h, lint w) : vector(h, vector<lint>(w)) {}
	vec2(lint h, lint w, lint v) : vector(h, vector<lint>(w, v)) {}
};

template<class T> using priq = priority_queue<T>;
template<class T> using rpriq = priority_queue<T, vector<T>, greater<T>>;
template<class Key, class Val> using hashmap = unordered_map<Key, Val>;
template<class Key> using hashset = unordered_set<Key>;

template<class It>
constexpr typename It::value_type rmax(It begin, It end) {
	return *max_element(begin, end);
}

template<class T1, class T2>
constexpr auto mmax(T1 arg1, T2 arg2) {
	using T = decltype(arg1 + arg2);
	return max(T(arg1), T(arg2));
}

template<class T, class ...Types>
constexpr auto mmax(T arg0, Types ...args) {
	return mmax(arg0, mmax(args...));
}

template<class It>
constexpr typename It::value_type rmin(It begin, It end) {
	return *min_element(begin, end);
}

template<class T1, class T2>
constexpr auto mmin(T1 arg1, T2 arg2) {
	using T = decltype(arg1 + arg2);
	return min(T(arg1), T(arg2));
}

template<class T, class ...Types>
constexpr auto mmin(T arg0, Types ...args) {
	return mmin(arg0, mmin(args...));
}

mt19937 mtrand((random_device())());

const double pi = 3.141592653589793238462;
const lint intmax = 9223372036854775807;
const lint inf = 1100100100100100100LL;

constexpr lint div2(lint p, lint q)
{
	return (p + q - 1) / q;
}

#if(__cplusplus < 201703L)

lint gcd(lint a, lint b) {
	while (1) {
		if (a < b) swap(a, b);
		if (!b) break;
		a %= b;
	}
	return a;
}

lint lcm(lint a, lint b)
{
	return a / gcd(a, b) * b;
}

#endif

template<class T>
struct nval {
	lint n;		// counts
	T val;
	nval() : n(0) {};
	nval(lint _n, T _val) : n(_n), val(_val) {};
};

template<class It, class It2>
auto spacel(It i, It2 end)
{
	if (i + 1 == end)
	{
		return '\n';
	}
	else
	{
		return ' ';
	}
}

ostream& setp(ostream& ost)
{
	cout << setprecision(60) << fixed;
	return ost;
}

const ulint mod = 1000000007;
//const ulint mod = 998244353;
const ld eps = 0.0000001;

lint an[110][110];
lint as[110][110];

int main()
{
	lint n;
	cin >> n;

	struct A
	{
		lint d2, d5;
	};
	vect<A> p(n);

	rep(i, n)
	{
		string s;
		cin >> s;
		lint cp = 0;
		lint a = 0, b = 1;
		rep(j, s.length())
		{
			if (cp)
				b *= 10;
			if (s[j] != '.')
			{
				a *= 10;
				a += (s[j] - '0');
			}
			else
			{
				cp = 1;
			}
		}

		lint h2 = 0, h5 = 0, n2 = 0, n5 = 0;
		while (a % 2 == 0) {
			a /= 2;
			h2++;
		}
		while (a % 5 == 0) {
			a /= 5;
			h5++;
		}
		while (b % 2 == 0) {
			b /= 2;
			n2++;
		}
		while (b % 5 == 0) {
			b /= 5;
			n5++;
		}

		p[i] = { h2 - n2 ,h5 - n5 };
		an[50 + p[i].d2][50 + p[i].d5]++;
	}

	rep(i, 100)
	{
		rep(j, 100)
		{
			as[i + 1][j + 1] =
				+ as[i + 1][j]
				+ as[i][j + 1]
				- as[i][j]
				+ an[i][j];
		}
	}

	lint ans = 0;

	rep(i, n)
	{
		ans += 
			as[100][100] 
			- as[100][-p[i].d5 + 50]
			- as[-p[i].d2 + 50][100] 
			+ as[-p[i].d2 + 50][-p[i].d5 + 50];

		if (p[i].d2 >= 0 && p[i].d5 >= 0)
		{
			ans--;
		}
	}

	cout << ans / 2 << endl;

	return 0;
}


Measured memory_bytes: 6124