/*
    author:  Maksim1744
    created: 09.08.2020 15:05:48
*/

#include <bits/stdc++.h>

using namespace std;

#define ll   long long
#define ld   long double

#define mp   make_pair
#define pb   push_back
#define eb   emplace_back

#define sum(a)     ( accumulate ((a).begin(), (a).end(), 0ll))
#define mine(a)    (*min_element((a).begin(), (a).end()))
#define maxe(a)    (*max_element((a).begin(), (a).end()))
#define mini(a)    ( min_element((a).begin(), (a).end()) - (a).begin())
#define maxi(a)    ( max_element((a).begin(), (a).end()) - (a).begin())
#define lowb(a, x) ( lower_bound((a).begin(), (a).end(), (x)) - (a).begin())
#define uppb(a, x) ( upper_bound((a).begin(), (a).end(), (x)) - (a).begin())

template<typename T>             vector<T>& operator--            (vector<T>& v){for (auto& i : v) --i;            return  v;}
template<typename T>             vector<T>& operator++            (vector<T>& v){for (auto& i : v) ++i;            return  v;}
template<typename T>             istream& operator>>(istream& is,  vector<T>& v){for (auto& i : v) is >> i;        return is;}
template<typename T>             ostream& operator<<(ostream& os,  vector<T>& v){for (auto& i : v) os << i << ' '; return os;}
template<typename T, typename U> istream& operator>>(istream& is, pair<T, U>& p){is >> p.first >> p.second;        return is;}
template<typename T, typename U> ostream& operator<<(ostream& os, pair<T, U>& p){os << p.first << ' ' << p.second; return os;}
template<typename T, typename U> pair<T,U> operator-(pair<T,U> a, pair<T,U> b){return mp(a.first-b.first, a.second-b.second);}
template<typename T, typename U> pair<T,U> operator+(pair<T,U> a, pair<T,U> b){return mp(a.first+b.first, a.second+b.second);}
template<typename T, typename U> void umin(T& a, U b){if (a > b) a = b;}
template<typename T, typename U> void umax(T& a, U b){if (a < b) a = b;}

#ifdef HOME
#define TAG_LENGTH       25
#define LR_LEFT          left
#define LR_RIGHT         right
#define LR_VALUE         value
#define LR_SECOND_VALUE  mn
#include "C:/C++ libs/print.cpp"
#else
#define showl            42;
#define shows            42;
#define show(...)        42;
#define showm(...)       42;
#define showt(...)       42;
#define printTree(...)   42;
#define printGraph(...)  42;
#define printLRTree(...) 42;
#define printMatrix(...) 42;
#define printWGraph(...) 42;
#define debug     if (false)
#endif

int main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

    int n;
    cin >> n;
    map<pair<int, int>, ll> m;
    for (int i = 0; i < n; ++i) {
        string s;
        cin >> s;
        if (count(s.begin(), s.end(), '.') == 0) {
            s = s + ".0";
        }
        int cnt = 0;
        while (s[s.size() - 1 - cnt] != '.') ++cnt;
        s = s.substr(0, s.size() - cnt - 1) + s.substr(s.size() - cnt, s.size());
        ll num = 0;
        for (auto c : s) {
            num = num * 10 + (c - '0');
        }
        int p2 = -cnt, p5 = -cnt;
        while (num % 2 == 0) {
            num /= 2;
            ++p2;
        }
        while (num % 5 == 0) {
            num /= 5;
            ++p5;
        }
        m[{p2, p5}]++;
    }
    vector<pair<pair<int, int>, ll>> v;
    for (auto x : m) {
        v.pb(x);
    }
    ll ans = 0;
    for (int i = 0; i < v.size(); ++i) {
        for (int j = 0; j < i; ++j) {
            if (v[i].first.first + v[j].first.first >= 0 && v[i].first.second + v[j].first.second >= 0) {
                ans += v[i].second * v[j].second;
            }
        }
    }
    // show(v);
    // show(ans);
    // ans /= 2;
    for (int i = 0; i < v.size(); ++i) {
        if (v[i].first.first >= 0 && v[i].first.second >= 0)
            ans += v[i].second * (v[i].second - 1) / 2;
    }

    cout << ans << endl;

    return 0;
}


Measured memory_bytes: 3656