#line 2 "header.hpp"

//%snippet.set('header')%
//%snippet.fold()%
#ifndef HEADER_H
#define HEADER_H

// template version 2.0
using namespace std;
#include <bits/stdc++.h>

// varibable settings
const long long INF = 1e18;
template <class T> constexpr T inf = numeric_limits<T>::max() / 2.1;

#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for (ll i = (ll)(a); i < (ll)(b); ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
#define _rrep(i, n) rrepi(i, 0, n)
#define rrepi(i, a, b) for (ll i = (ll)((b)-1); i >= (ll)(a); --i)
#define r_rep(...) _overload3(__VA_ARGS__, rrepi, _rrep, )(__VA_ARGS__)
#define each(i, a) for (auto &&i : a)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
#define mt(...) make_tuple(__VA_ARGS__)
#define ub upper_bound
#define lb lower_bound
#define lpos(A, x) (lower_bound(all(A), x) - A.begin())
#define upos(A, x) (upper_bound(all(A), x) - A.begin())
template <class T> inline void chmax(T &a, const T &b) { if ((a) < (b)) (a) = (b); }
template <class T> inline void chmin(T &a, const T &b) { if ((a) > (b)) (a) = (b); }
template <typename X, typename T> auto make_table(X x, T a) { return vector<T>(x, a); }
template <typename X, typename Y, typename Z, typename... Zs> auto make_table(X x, Y y, Z z, Zs... zs) { auto cont = make_table(y, z, zs...); return vector<decltype(cont)>(x, cont); }

#define cdiv(a, b) (((a) + (b)-1) / (b))
#define is_in(x, a, b) ((a) <= (x) && (x) < (b))
#define uni(x) sort(all(x)); x.erase(unique(all(x)), x.end())
#define slice(l, r) substr(l, r - l)

typedef long long ll;
typedef long double ld;
using vl = vector<ll>;
using vvl = vector<vl>;
using pll = pair<ll, ll>;

template <typename T>
using PQ = priority_queue<T, vector<T>, greater<T>>;
void check_input() { assert(cin.eof() == 0); int tmp; cin >> tmp; assert(cin.eof() == 1); }

#if defined(PCM) || defined(LOCAL)
#else
#define dump(...) ;
#define dump_1d(...) ;
#define dump_2d(...) ;
#define cerrendl ;
#endif

#endif /* HEADER_H */
//%snippet.end()%
#line 2 "solve.cpp"
template<class T=ll> using vec = vector<T>;
struct Fast { Fast() { std::cin.tie(0); ios::sync_with_stdio(false); } } fast;

template <typename T>
struct RectangleSum {
    vector<vector<T>> sum;
    T GetSum(int top, int bottom, int left, int right){ // {{{
        //[left, right), [top, bottom)
        T res = sum[bottom-1][right-1];
        if (left > 0) res -= sum[bottom-1][left - 1];
        if (top > 0) res -= sum[top - 1][right-1];
        if (left > 0 && top > 0) res += sum[top - 1][left - 1];
        return res;
    } /*}}}*/

    RectangleSum(const vector<vector<T>> &s) { /*{{{*/
        int h = s.size();
        int w = s[0].size();
        sum.resize(h);
        for (int i = 0; i < h; i++) sum[i].resize(w, 0);
        for (int y = 0; y < h; y++) {
            for (int x = 0; x < w; x++) {
                sum[y][x] = s[y][x];
                if (y > 0) sum[y][x] += sum[y - 1][x];
                if (x > 0) sum[y][x] += sum[y][x - 1];
                if (y > 0 && x > 0) sum[y][x] -= sum[y - 1][x - 1];
            }
        }
        dump_2d(sum, h, w);
    } /*}}}*/
};

int solve() {
    ll n;cin>>n;
    vec<pll> x;
    ll MAX = 142;
    vvl p = make_table(MAX, MAX, 0LL);
    rep(i, n){/*{{{*/
        cerrendl;
        string s;cin>>s;
        dump(s);
        auto it = s.find('.');
        ll c2 = 0;
        ll c5 = 0;
        ll a, b;
        if (it != string::npos) {
            a = stoll(s.substr(0, it) + s.substr(it+1, sz(s)-it));
            b = pow(10, sz(s)-it-1);
            ll g = gcd(a, b);
            a /= g;
            b /= g;
        }
        else{
            // x.pb(mp(stoll(s), 1));
            a = stoll(s);
            b = 1;
        }

        dump(a, b);
        while(a%2 == 0){
            c2++;
            a /= 2;
        }
        while(a%5 == 0){
            c5++;
            a /= 5;
        }
        while(b%2 == 0){
            c2--;
            b /= 2;
        }
        while(b%5 == 0){
            c5--;
            b /= 5;
        }
        dump(a, b);
        dump(c2, c5);
        p[c2+MAX/2][c5+MAX/2]++;
        x.pb(mp(c2, c5));
    }/*}}}*/
    dump_2d(p, MAX, MAX);
    RectangleSum rs(p);

    ll cnt = 0;
    rep(i, n){
        auto [c2, c5] = x[i];
        cnt += rs.GetSum(-c2+MAX/2, MAX-1, -c5+MAX/2, MAX-1);

        if (c2>=0 && c5>=0) cnt--;
    }

    cout << cnt/2 << endl;
    return 0; 
}


int main(){/*{{{*/
    solve();
    check_input();
    return 0;
}/*}}}*/


Measured memory_bytes: 7964