#line 1 "main.cpp"

/**
 * @title Template
 */

#include <iostream>
#include <algorithm>
#include <utility>
#include <numeric>
#include <vector>
#include <array>
#include <cassert>

#line 2 "/Users/kodamankod/Desktop/Programming/Library/other/chmin_chmax.cpp"

template <class T, class U>
constexpr bool chmin(T &lhs, const U &rhs) {
  if (lhs > rhs) { 
    lhs = rhs; 
    return true; 
  }
  return false;
}

template <class T, class U>
constexpr bool chmax(T &lhs, const U &rhs) {
  if (lhs < rhs) { 
    lhs = rhs; 
    return true; 
  }
  return false;
}

/**
 * @title Chmin/Chmax
 */
#line 2 "/Users/kodamankod/Desktop/Programming/Library/other/range.cpp"

#line 4 "/Users/kodamankod/Desktop/Programming/Library/other/range.cpp"

class range {
public:
  class iterator {
  private:
    int64_t M_position;

  public:
    constexpr iterator(int64_t position) noexcept: M_position(position) { }
    constexpr void operator ++ () noexcept { ++M_position; }
    constexpr bool operator != (iterator other) const noexcept { return M_position != other.M_position; }
    constexpr int64_t operator * () const noexcept { return M_position; }

  };

  class reverse_iterator {
  private:
    int64_t M_position;
  
  public:
    constexpr reverse_iterator(int64_t position) noexcept: M_position(position) { }
    constexpr void operator ++ () noexcept { --M_position; }
    constexpr bool operator != (reverse_iterator other) const noexcept { return M_position != other.M_position; }
    constexpr int64_t operator * () const noexcept { return M_position; }

  };
  
private:
  const iterator M_first, M_last;

public:
  constexpr range(int64_t first, int64_t last) noexcept: M_first(first), M_last(std::max(first, last)) { }
  constexpr iterator begin() const noexcept { return M_first; }
  constexpr iterator end() const noexcept { return M_last; }
  constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(*M_last - 1); } 
  constexpr reverse_iterator rend() const noexcept { return reverse_iterator(*M_first - 1); } 

};

/**
 * @title Range
 */
#line 2 "/Users/kodamankod/Desktop/Programming/Library/other/rev.cpp"

#include <type_traits>
#include <iterator>
#line 6 "/Users/kodamankod/Desktop/Programming/Library/other/rev.cpp"

template <class T>
class rev_impl {
public:
  using iterator = typename std::decay<T>::type::reverse_iterator;

private:
  const iterator M_begin;
  const iterator M_end;

public:
  constexpr rev_impl(T &&cont) noexcept: M_begin(std::rbegin(cont)), M_end(std::rend(cont)) { }
  constexpr iterator begin() const noexcept { return M_begin; }
  constexpr iterator end() const noexcept { return M_end; }

};

template <class T>
constexpr decltype(auto) rev(T &&cont) {
  return rev_impl<T>(std::forward<T>(cont));
}

/**
 * @title Reverser
 */
#line 17 "main.cpp"

using i32 = int32_t;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;

constexpr i32 inf32 = (i32(1) << 30) - 1;
constexpr i64 inf64 = (i64(1) << 62) - 1;

int main() {
  size_t N;
  std::cin >> N;
  std::vector<std::string> str(N);
  for (auto &x: str) {
    std::cin >> x;
  }
  std::array<std::array<i32, 19>, 19> count{};
  std::vector<i32> two(N), five(N);
  for (auto i: range(0, N)) {
    i64 cur = 0;
    i32 after_dot = 0;
    for (auto j: range(0, str[i].size())) {
      auto c = str[i][j];
      if (c == '.') {
        after_dot = str[i].size() - j - 1;
      }
      else {
        cur = cur * 10 + (c - '0');
      }
    }
    while (after_dot < 9) {
      cur *= 10;
      ++after_dot;
    }
    while (cur % 2 == 0) {
      ++two[i];
      cur /= 2;
    }
    while (cur % 5 == 0) {
      ++five[i];
      cur /= 5;
    }
    chmin(two[i], 18);
    chmin(five[i], 18);
    ++count[two[i]][five[i]];
  }
  i64 ans = 0;
  for (auto i: range(0, N)) {
    for (auto t: range(0, 19)) {
      for (auto f: range(0, 19)) {
        if (two[i] + t >= 18 && five[i] + f >= 18) {
          ans += count[t][f];
        }
      }
    }
    if (two[i] * 2 >= 18 && five[i] * 2 >= 18) {
      --ans;
    }
  }
  std::cout << ans / 2 << '\n';
  return 0;
}


Measured memory_bytes: 11076