#ifdef LOCAL
    #define _GLIBCXX_DEBUG
    #define __clock__
#else
    #pragma GCC optimize("Ofast")
#endif
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;

// tourist set
template <typename A, typename B>
string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string& s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << '\n'; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i,b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<'\n'
#define p2(s, t) cout << (s) << " " << (t) << '\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\n'
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())
#define MP make_pair
#define p_yes() p("YES")
#define p_no() p("NO")

ll SUM(VI& V){
  return accumulate(ALL(V), 0LL);
}

ll MIN(VI& V){return *min_element(ALL(V));}
ll MAX(VI& V){return *max_element(ALL(V));}

void print_vector(VI& V){
  ll n = V.size();
  rep(i, n){
    if(i) cout << ' ';
    cout << V[i];
  }
  cout << endl;
}

ll gcd(ll a,ll b){
    if(b == 0) return a;
    return gcd(b,a%b);
}

ll lcm(ll a,ll b){
    ll g = gcd(a,b);
    return a / g * b;
}

// long double
using ld = long double;
#define EPS (1e-14)
#define equals(a,b) (fabs((a)-(b)) < EPS)

void no(){p_no(); exit(0);}
void yes(){p_yes(); exit(0);}

const ll mod = 1e9 + 7;
const ll inf = 1e18;
const double PI = acos(-1);

// snuke's mint
// auto mod int
// https://youtu.be/L8grWxBlIZ4?t=9858
// https://youtu.be/ERZuLAxZffQ?t=4807 : optimize
// https://youtu.be/8uowVvQ_-Mo?t=1329 : division
// const int mod = 1000000007;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res+=a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res-=a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res*=a;
  }
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }

  // for prime mod
  mint inv() const {
    return pow(mod-2);
  }
  mint& operator/=(const mint a) {
    return (*this) *= a.inv();
  }
  mint operator/(const mint a) const {
    mint res(*this);
    return res/=a;
  }
};

// vをaでなんかい割れるか
ll f(ll v, ll a){
  ll cnt=0;
  while(v%a==0){
    v/=a;
    cnt++;
  }
  return cnt;
}

// 2次元累積和
struct AccSum2D{
    VV Ac; // accumulate
    ll W;
    ll H;
    AccSum2D(){}
    AccSum2D(VV &A){
      H = A.size();
      W = A[0].size();
      Ac.resize(H+1, VI(W+1));
      // indexを1つずらしてコピー
      rep(i, H){
        rep(j, W){
          Ac[i+1][j+1] = A[i][j];
        }
      }
      // 横に累積
      rep(i, H+1){
        rep(j, W){
          Ac[i][j+1] += Ac[i][j];
        }
      }
      // 縦に累積
      rep(x, W+1){
        rep(y, H){
          Ac[y+1][x] += Ac[y][x];
        }
      }
    }
    // 入力したAの0-indexで指定 (閉区間)
    // sum of (a,b) to (c,d)
    // a, cはy方向
    // b, dはx方向
    ll sum(ll a, ll b, ll c, ll d){
      if(a<0)a=0;
      if(b<0)b=0;
      if(c<0)c=0;
      if(d<0)d=0;
      // 内部ではindexが1ずれる
      a++; b++; c++; d++;
      return Ac[c][d] - Ac[a-1][d] - Ac[c][b-1] + Ac[a-1][b-1];
    }
};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N; 
    cin>>N;

    VI A(N);
    rep(i, N){
      ld a;cin>>a;
      a += EPS; // これがないとWA
      A[i] = 1e9 * a;
    }

    debug(A);

    VI B(N);
    rep(i,N){
      ll a = A[i];
      B[i] = f(a,2);
    }

    VI C(N);
    rep(i,N){
      ll a = A[i];
      C[i] = f(a,5);
    }

    debug(B);
    debug(C);

    // ll cnt=0;
    // rep(i,N){
    //   FOR(j,i+1,N){
    //     if(B[i]+B[j]>=18 && C[i]+C[j]>=18) cnt++;
    //   }
    // }
    // p(cnt);

    VV G(100, VI(100));
    rep(i,N){
      ll b = B[i];
      ll c = C[i];
      G[b][c]++;
    }
    auto Acc = AccSum2D(G);

    ll sum=0;
    rep(i,N){
      ll b = B[i];
      ll c = C[i];

      sum += Acc.sum(18-b, 18-c, 50, 50);
    }

    rep(i,N){
      ll b = B[i];
      ll c = C[i];
      if(2*b>=18 && 2*c>=18) sum--;
    }
    p(sum/2);
    


    return 0;
}


Measured memory_bytes: 8360