#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <ctime>
#include <cassert>
#include <complex>
#include <string>
#include <cstring>
#include <chrono>
#include <random>
#include <queue>
#include <bitset>
#include <stack>
#include <functional>

#ifdef LOCAL
    #define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
    #define eprintf(...)
#endif

#define rep_(i, a_, b_, a, b, ...) for (int i = (a), i##_len = (b); i < i##_len; ++i)
#define rep(i, ...) rep_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
#define reprev_(i, a_, b_, a, b, ...) for (int i = (b-1), i##_min = (a); i >= i##_min; --i)
#define reprev(i, ...) reprev_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
#define all(x) (x).begin(), (x).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 fls(x) (64 - __builtin_clzll(x))
#define pcnt(x) __builtin_popcountll(x)
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair <ll, ll> P;
typedef long double ld;

template <class T>
map<T, int> prime_factor(T n) {
    map<T, int> ret;
    for (T i = 2; i * i <= n; i++) {
        while (n % i == 0) {
            ret[i]++;
            n /= i;
        }
    }
    if (n != 1) ret[n] = 1;
    return ret;
}

ll f (char *s) {
    int n = strlen(s);
    ll ret;
    sscanf(s, "%lld", &ret);
    while (n < 9) {
        ret *= 10;
        n++;
    }
    return ret;
}

int main (void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n; cin >> n;
    vector<P> a(n);
    rep (i, n) {
        // char buf[100];
        string buf;
        // scanf("%s", buf);
        cin >> buf;
        eprintf("%s\n", buf.c_str()); fflush(stderr);
        bool pe = false;
        // rep (j, strlen(buf)) eprintf("%02d ", buf[j]);
        rep (j, buf.size()) if (buf[j] == '.') pe = true;
        if (!pe) {
            sscanf(buf.c_str(), "%lld", &a[i].first);
        } else {
            char buf2[100];
            sscanf(buf.c_str(), "%lld.%s", &a[i].first, buf2);
            a[i].second = f(buf2);
        }
    }
    eprintf("#\n"); fflush(stderr);
    vector<ll> k(n);
    rep (i, n) k[i] = a[i].first * 1000000000 + a[i].second;
    vector<P> fa(n);
    rep (i, n) {
        eprintf("%lld\n", k[i]); fflush(stderr);
        while (k[i] % 2 == 0) {
            fa[i].first++;
            k[i] /= 2;
        }
        while (k[i] % 5 == 0) {
            fa[i].second++;
            k[i] /= 5;
        }
    }
    eprintf("a"); fflush(stderr);
    int MAX = 145;
    vector<vector<ll>> b(MAX, vector<ll>(MAX));
    rep (i, n) b[fa[i].first][fa[i].second]++;
    // rep (i, 15) {
    //     rep (j, 15) eprintf("%2lld ", b[i][j]); eprintf("\n");
    // }
    reprev (i, MAX) {
        reprev (j, MAX) {
            if (i > 0) b[i - 1][j] += b[i][j];
        }
    }
    reprev (i, MAX) {
        reprev (j, MAX) {
            if (j > 0) b[i][j - 1] += b[i][j];
        }
    }
    // rep (i, 15) {
    //     rep (j, 15) eprintf("%2lld ", b[i][j]); eprintf("\n");
    // }
    eprintf("b"); fflush(stderr);
    ll ans = 0;
    rep (i, n) {
        ans += b[max(0LL, 18 - fa[i].first)][max(0LL, 18 - fa[i].second)];
        if (2 * fa[i].first >= 18 && 2 * fa[i].second >= 18) ans--;
        // eprintf("%d %lld %lld %lld %d\n", i, fa[i].first, fa[i].second, 
        // b[max(0LL, 18 - fa[i].first)][max(0LL, 18 - fa[i].second)], 2 * fa[i].first >= 18 && 2 * fa[i].second >= 18);
    }
    cout << ans / 2 << "\n";
    return 0;
}

Measured memory_bytes: 11444