#pragma GCC optimize("Ofast")

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <random>

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;

typedef
tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> orderedSet;

#define pb push_back
#define F first
#define S second
#define all(a) (a).begin(), (a).end()

#define for1(i0, l0, r0) for (int i0 = l0; i0 < r0; ++i0)
#define for2(i0, l0, r0) for (int i0 = l0; i0 <= r0; ++i0)
#define forn(i0, n0) for (int i0 = 0; i0 < n0; ++i0)
#define forn1(i0, n0) for (int i0 = 1; i0 < n0; ++i0)
#define forr(i0, n0) for (int i0 = n0; i0 >= 0; --i0)
#define forr1(i0, r0, l0) for (int i0 = r0; i0 > l0; --i0)
#define forr2(i0, r0, l0) for (int i0 = r0; i0 >= l0; --i0)

#define Sort(a) sort(all(a))
#define Reverse(a) reverse(all(a))
#define relaxMax(a, b) a = max(a, b)
#define relaxMin(a, b) a = min(a, b)

typedef long double ld;
#define ui unsigned int
#define ull unsigned long long

typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;
typedef pair<string, string> pss;

typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<double> vd;
typedef vector<ld> vld;
typedef vector<bool> vb;
typedef vector<string> vs;

typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<pdd> vpdd;

typedef vector<vi> vvi;
typedef vector<vd> vvd;
typedef vector<vll> vvll;
typedef vector<vb> vvb;

#define vpss vector<pss>
#define vvs vector<vs>
#define vvpii vector<vpii>
#define vvpll vector<vpll>
#define vpt vector<pt>
#define vvvi vector<vvi>
#define vsi vector<set<int>>
#define ss second
#define ff first

#define printvi(arr) for (int x0 : arr) cout << x0 << ' '; cout << '\n';
#define printvll(arr) for (ll x0 : arr) cout << x0 << ' '; cout << '\n';
#define printpair(pair0) cout << pair0.F << ' ' << pair0.S << '\n';
#define printvp(arr) for (auto pair0 : arr) printpair(pair0);
#define initArray(arr, N0, X0) memset(arr, X0, N0 * sizeof(int))
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void init() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    //cout.precision(16);
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
}

int digitsAfterDecimal(string s){
    int ans = 0;
    int x = 0;
    for (char c : s){
        if (c == '.')
            x = 1;
        else
            ans += x;
    }
    return ans;
}

int cnt2(ll x){
    int ans = 0;
    while (x % 2 == 0){
        ans++;
        x /= 2;
    }
    return ans;
}

int cnt5(ll x){
    int ans = 0;
    while (x % 5 == 0){
        ans++;
        x /= 5;
    }
    return ans;
}

void solve() {
    int n;
    cin >> n;
    map<pii, ll> cnt;
    forn(i, n){
        string s;
        cin >> s;
        ll p = 0;
        for(char c : s){
            if (c != '.') p = 10 * p + (c - '0');
        }
        ll q = 1;
        forn(j, digitsAfterDecimal(s)) q *= 10;
        ll g = __gcd(p, q);
        p /= g, q /= g;
        int c21 = cnt2(p), c22 = cnt2(q), c51 = cnt5(p), c52 = cnt5(q);
        int d2 = c21 - c22, d5 = c51 - c52;
        cnt[{d2, d5}]++;
    }
    ll ans = 0;
    for (auto p : cnt){
        int x = p.F.F, y = p.F.S;
        ll c = p.S;
        if (x >= 0 && y >= 0) ans += c * (c - 1);
        for (auto p2: cnt){
            int x2 = p2.F.F, y2 = p2.F.S;
            ll c2 = p2.S;
            if (x == x2 && y == y2) continue;
            if (x + x2 >= 0 && y + y2 >= 0) ans += c * c2;
        }
    }
    cout << ans / 2 << '\n';
}

bool multitest = false;

int main() {
    init();
    int t = 1;
    if (multitest) cin >> t;
    forn(i, t) solve();
}

Measured memory_bytes: 3664