#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cctype>
#include <cassert>
#include <climits>
#include <string>
#include <bitset>
#include <cfloat>
#include <random>
#include <iomanip>
#include <unordered_set>
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
typedef vector<pair<int,int> > vpii;
typedef vector<pair<ll,ll> > vpll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vc> vvc;
typedef vector<vs> vvs;
typedef vector<vll> vvll;
typedef map<int,int> mii;
typedef set<int> si;
#define rep(i,n) for(ll i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define arep(i,v) for(auto i : v)
#define irep(it, stl) for(auto it = stl.begin(); it != stl.end(); it++)
#define drep(i,n) for(int i = (n) - 1; i >= 0; --i)
#define fin(ans) cout << (ans) << '\n'
#define STLL(s) strtoll(s.c_str(), NULL, 10)
#define mp(p,q) make_pair(p, q)
#define pb(n) push_back(n)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define Sort(a) sort(a.begin(), a.end())
#define Rort(a) sort(a.rbegin(), a.rend())
#define MATHPI acos(-1)
#define fi first
#define se second
constexpr int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
constexpr int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
template <class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;} return 0;}
template <class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;} return 0;}
template <class T> inline void dump(T &v){irep(i, v){cout<<(*i)<<((i==--v.end())?'\n':' ');}}
inline string getline(){string s; getline(cin,s); return s;}
inline void yn(const bool b){b?fin("yes"):fin("no");}
inline void Yn(const bool b){b?fin("Yes"):fin("No");}
inline void YN(const bool b){b?fin("YES"):fin("NO");}
struct io{io(){ios::sync_with_stdio(false);cin.tie(0);}};
const int INF = INT_MAX;
constexpr ll LLINF = 1LL<<60;
constexpr ll MOD = 1000000007;
constexpr ld EPS = 1e-11;


template <typename T>
class Sum {
   public:
    // 単位元
    T unit;
 
    Sum(void) {
        // 単位元
        unit = 0;
    }
 
    // 演算関数
    T calc(T a, T b) { return a + b; }
};
 
template <typename T, class MONOID>
class SegmentTree {
   public:
    // セグメント木の葉の要素数
    int n;
 
    // セグメント木
    vector<T> tree;
 
    // モノイド
    MONOID mono;
 
    SegmentTree() : n(1 << (int)ceil(log2(64))), tree(vector<T>(n << 1)) {
        for (int i = 0; i < 64; ++i) {
            update(i, mono.unit);
        }
    }
 
    // k番目の値(0-indexed)をxに変更
    void update(int k, T x) {
        k += n;
        tree[k] += x;
        for (k = k >> 1; k > 0; k >>= 1) {
            tree[k] = mono.calc(tree[k << 1 | 0], tree[k << 1 | 1]);
        }
    }
 
    // [l, r)の最小値(0-indexed)を求める．
    T query(int l, int r) {
        T res = mono.unit;
        l += n;
        r += n;
        while (l < r) {
            if (l & 1) {
                res = mono.calc(res, tree[l++]);
            }
            if (r & 1) {
                res = mono.calc(res, tree[--r]);
            }
            l >>= 1;
            r >>= 1;
        }
        return res;
    }
 
    T operator[](int k) {
        // st[i]で添字iの要素の値を返す
        if (k - n >= 0 || k < 0) {
            return -INF;
        }
        return tree[tree.size() - n + k];
    }
 
    void show(void) {
        int ret = 2;
        for (int i = 1; i < 2 * n; ++i) {
            if (tree[i] == mono.unit)
                cout << "UNIT ";
            else
                cout << tree[i] << " ";
            if (i == ret - 1) {
                cout << endl;
                ret <<= 1;
            }
        }
        cout << endl;
    }
};



int main() {
    int n;
    cin >> n;
    ll ans = 0;
    vector<SegmentTree<ll, Sum<ll>>> st(64);
    rep(_, n) {
        double t;
        cin>>t;
        t *= 1e9;
 
        ll two = 0, five = 0;
        ll it = t+0.5;
        while (it % 2 == 0) {
            it /= 2;
            two++;
        }
        while (it % 5 == 0) {
            it /= 5;
            five++;
        }
        // cout << two << " " << five << endl;
        for (ll i = max(18 - two, 0LL); i < 64; i++) {
            ans += st[i].query(max(18 - five, 0LL), 64);
        }
        st[two].update(five, 1);
    }
    fin(ans);
}

Measured memory_bytes: 3760