/*
これを入れて実行
g++ code.cpp
./a.out
 */
 
#include <iostream>
#include <stdio.h>
#include <vector>
#include <string>
#include <cstring>
#include <queue>
#include <deque>
#include <stack>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cmath>
#include <math.h>
#include <tuple>
#include <iomanip>
#include <bitset>
#include <functional>
#include <cassert>

#define all(x) (x).begin(),(x).end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
 
using namespace std;
typedef long long ll;
typedef long double ld;
 
int dy4[4] = {-1, 0, +1, 0};
int dx4[4] = {0, +1, 0, -1};
int dy8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dx8[8] = {0, 1, 1, 1, 0, -1, -1, -1};
 
const long long INF = 1LL << 60;
const ll MOD = 1e9 + 7;
 
bool greaterSecond(const pair<int, int>& f, const pair<int, int>& s){
    return f.second > s.second;
}
 
ll gcd(ll a, ll b){
	if (b == 0)return a;
	return gcd(b, a % b);
}
 
ll lcm(ll a, ll b){
    return a / gcd(a, b) * b;
}

ll conbinationMemo[100][100];

void cmemoInit(){
    rep(i, 100){
        rep(j, 100){
            conbinationMemo[i][j] = -1;
        }
    }
}
 
ll nCr(ll n, ll r){
    if(conbinationMemo[n][r] != -1) return conbinationMemo[n][r];
    if(r == 0 || r == n){
        return 1;
    } else if(r == 1){
        return n;
    }
    return conbinationMemo[n][r] = (nCr(n - 1, r) + nCr(n - 1, r - 1));
}
 
ll nPr(ll n, ll r){
    r = n - r;
    ll ret = 1;
    for (ll i = n; i >= r + 1; i--) ret *= i;
    return ret;
}
//-----------------------ここから-----------
int main(void){
    ll n;
    cin >> n;
    vector<ll> a(n);
    rep(i, n){
        string s;
        cin >> s;
        string tmp;
        string tmp2;
        bool f = false;
        rep(j, s.size()){
            if(!f){
                if(s[j] != '.'){
                    tmp.push_back(s[j]);
                } else {
                    f = true;
                }
            } else {
                tmp2.push_back(s[j]);
            }
        }
        while(tmp2.size() != 9) tmp2.push_back('0');
        //cout << tmp << tmp2 << endl;
        ll in = stoll(tmp) * 1e9;
        ll d = 0;
        if(tmp2.size() != 0)d = stoll(tmp2);
        a[i] = in + d;
    } 

    // rep(i, n){
    //     cout << a[i] << endl;
    // }


   vector<pair<ll,ll>> vec(n);
   map<pair<ll,ll>, ll> mp;
    rep(i, n){
        ll now = a[i];
        ll cnt = 0;
        while(now % 2 == 0){
            now /= 2;
            cnt++;
        }

        vec[i].first = cnt;
        cnt = 0;    
        while(now % 5 == 0){
            now /= 5;
            cnt++;
        }

        vec[i].second = cnt;
        mp[vec[i]]++;
        //cout << vec[i].first << " " << vec[i].second << endl;
    }

    ll ans = 0;
    for(auto &i : mp){
        for(auto &j : mp){
            if(i.first >= j.first) continue;
            if(i.first.first + j.first.first >= 18 && i.first.second + j.first.second >= 18)
            ans += i.second * j.second;
        }
    }

    for(auto &i : mp){
        if(i.second < 2) continue;
        if(i.first.first * 2 >= 18 && i.first.second * 2 >= 18)
        ans += i.second * (i.second - 1) / 2;
    }

    cout << ans << endl;


}

Measured memory_bytes: 7896