#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int MAX_N = 2e5 + 10;
const ll BASE = 1e9;

int N;
map<pair<int, int>, ll> mp;

int main() {
    scanf("%d", &N);
    for (int i = 1; i <= N; i++) {
        double _a; scanf("%lf", &_a);
        ll a = _a * BASE + 0.5;
        int cnt2 = 0, cnt5 = 0;
        while (a % 2 == 0) cnt2++, a /= 2;
        while (a % 5 == 0) cnt5++, a /= 5;
        mp[make_pair(cnt2, cnt5)]++;
    }
    ll ans = 0;
    for (auto i : mp) {
        for (auto j : mp) {
            if (i.first <= j.first && i.first.first + j.first.first >= 18 && i.first.second + j.first.second >= 18) {
                if (i.first == j.first) {
                    ans += i.second * (i.second - 1) / 2;
                } else {
                    ans += i.second * j.second;
                }
            }
        }
    }
    printf("%lld\n", ans);
}