//gzhffIThh
#include<bits/stdc++.h>

#define ui unsigned int
#define ll long long
#define ul unsigned ll
#define ld long double
 
#define pi pair <int, int>
#define fi first
#define se second
#define mp make_pair
 
#define vi vector <int>
#define pb push_back
#define pq priority_queue

#define sz(x) ((int)x.size())
#define all(x) (x).begin(), (x).end()

#define rep(i,a,b) for (int i=a;i<=b;i++)
#define per(i,a,b) for (int i=b;i>=a;i--)

#define dbg(x) cerr << #x" = " << x << endl
#define debug(...) fprintf(stderr, __VA_ARGS__)

#define fl(x) freopen(x".in", "r", stdin), freopen(x".out", "w", stdout);

using namespace std;
	namespace io {
	const int SI = 1 << 21 | 1;
	char IB[SI], *IS, *IT, OB[SI], *OS = OB, *OT = OS + SI - 1, c, ch[100];
	int f, t;
	#define gc() (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin), IS == IT ? EOF : *IS++) : *IS++)
	inline void flush() {
		fwrite(OB, 1, OS - OB, stdout), OS = OB;
	}
	inline void pc(char x) {
		*OS++ = x;
		if (OS == OT) flush();
	}

	template <class I>
	inline void rd(I &x) {
		for (f = 1, c = gc(); c < '0' || c > '9'; c = gc()) if (c == '-') f = -1;
		for (x = 0; c >= '0' && c <= '9'; x = (x << 3) + (x << 1) + (c & 15), c = gc());
		x *= f;
	}
	template <class I>
	inline void rd(I &x, I &y) {
		rd(x), rd(y);
	}
	template <class I>
	inline void rd(I &x, I &y, I &z) {
		rd(x), rd(y), rd(z);
	}
	template <class I>
	inline void rda(I *a, int n) {
		for (int i = 1; i <= n; i++) rd(a[i]);
	}
	inline void rdc(char &c) {
		for (c = gc(); c < 33 || c > 126; c = gc());
	}
	inline void rds(char *s, int &n) {
		for (c = gc(); c < 33 || c > 126; c = gc());
		for (n = 0; c >= 33 && c <= 126; s[++n] = c, c = gc());
		s[n+1] = '\0';
	}
	inline void rds(string &s) {
		for (c = gc(); c < 33 || c > 126; c = gc());
		for (s.clear(); c >= 33 && c <= 126; s.pb(c), c = gc());
	}

	template <class I>
	inline void print(I x, char k = '\n') {
		if (!x) pc('0');
		if (x < 0) pc('-'), x = -x;
		while (x) ch[++t] = x % 10 + '0', x /= 10;
		while (t) pc(ch[t--]);
		pc(k);
	}
	template <class I>
	inline void print(I x, I y) {
		print(x, ' '), print(y);
	}
	template <class I>
	inline void print(I x, I y, I z) {
		print(x, ' '), print(y, ' '), print(z);
	}
	template <class I>
	inline void printa(I *a, int n) {
		for (int i = 1; i <= n; i++) print(a[i], " \n"[i==n]);
	}
	inline void printc(char c) {
		pc(c);
	}
	inline void prints(char *s, int n) {
		for (int i = 1; i <= n; i++) pc(s[i]);
		pc('\n');
	}
	inline void prints(string s) {
		int n = s.length();
		while (t < n) pc(s[t++]);
		pc('\n'), t = 0;
	}
	struct Flush {
		~Flush() {
			flush();
		}
	} flusher;
}
using io::rd;
using io::rda;
using io::rdc;
using io::rds;
using io::print;
using io::printa;
using io::printc;
using io::prints;

const int P = 1000000007;
 
struct modint {
    int x;
    inline modint(int x = 0) : x(x) {}
    inline modint &operator = (int o) { return x = o, *this; }
    inline modint &operator += (modint o) { return x = x + o.x >= P ? x + o.x - P : x + o.x, *this; }
    inline modint &operator -= (modint o) { return x = x - o.x < 0 ? x - o.x + P : x - o.x, *this; }
    inline modint &operator *= (modint o) { return x = 1ll * x * o.x % P, *this; }
    inline modint &operator ^= (ll b) {
        modint a = *this, c;
        if (!~b) b = P - 2;
        c.x = 1 % P;
        while (b) {
            if (b & 1) c *= a;
            a *= a, b >>= 1;
        }
        return x = c.x, *this;
    }
    inline modint &operator /= (modint o) { return *this *= o ^= -1; }
    inline modint &operator += (int o) { return x = x + o >= P ? x + o - P : x + o, *this; }
    inline modint &operator -= (int o) { return x = x - o < 0 ? x - o + P : x - o, *this; }
    inline modint &operator *= (int o) { return x = 1ll * x * o % P, *this; }
    inline modint &operator /= (int o) { modint y = modint(o); return *this *= y ^= -1; }
    template <class I>
    inline friend modint operator + (modint a, I b) { return a += b; }
    template <class I>
    inline friend modint operator - (modint a, I b) { return a -= b; }
    template <class I>
    inline friend modint operator * (modint a, I b) { return a *= b; }
    inline friend modint operator ^ (modint a, ll b) { return a ^= b; }
    template <class I>
    inline friend modint operator / (modint a, I b) { return a /= b; }
    inline friend bool operator == (modint a, int b) { return a.x == b; }
    inline friend bool operator != (modint a, int b) { return a.x != b; }
    inline friend bool operator < (modint a, int b) { return a.x < b; }
    inline friend bool operator <= (modint a, int b) { return a.x <= b; }
    inline friend bool operator > (modint a, int b) { return a.x > b; }
    inline friend bool operator >= (modint a, int b) { return a.x >= b; }
    inline friend bool operator == (modint a, modint b) { return a.x == b.x; }
    inline friend bool operator != (modint a, modint b) { return a.x != b.x; }
    inline friend bool operator < (modint a, modint b) { return a.x < b.x; }
    inline friend bool operator <= (modint a, modint b) { return a.x <= b.x; }
    inline friend bool operator > (modint a, modint b) { return a.x > b.x; }
    inline friend bool operator >= (modint a, modint b) { return a.x >= b.x; }
    inline bool operator ! () { return !x; }
    inline modint operator - () { return x ? P - x : 0; }
};
inline void rd(modint &x) { rd(x.x); }
inline void print(modint x, char k = '\n') { print(x.x, k); }
template<class T> 
inline void cmin(T& a, T b) { 
	a = b < a ? b : a;
}
template<class T> 
inline void cmax(T& a, T b) {
	a = b > a ? b : a;
}
//head

const int N = 200010;
const int M = 57;

int n;
long double a[N];
ll g[N], tmp = 1000000000;
int c[M][M];
ll ans;

int main() {

	// fl("A");

	rd(n);
	for (int i = 1; i <= n; i++) {
        string s;
        rds(s);
        int p = -1;
        for (ui j = 0; j < s.size(); j++)
            if (s[j] == '.') p = j;
        if (!~p) p = s.size(), s += ".0";
        while ((int)s.size() - p < 10) s += "0";
        ll a = 0;
        for (ui j = 0; j < s.size(); j++)
            if (s[j] != '.') a = a * 10 + s[j] - '0';
        int c2 = 0, c5 = 0;
        while (a % 2 == 0) ++c2, a /= 2;
        while (a % 5 == 0) ++c5, a /= 5;
        c[c2][c5]++;
    }
	for (int i = 0; i < M; i++) {
		for (int j = 0; j < M; j++) {
			for (int k = max(0, 18 - i); k < M; k++) {
				for (int t = max(0, 18 - j); t < M; t++) {
					if(i == k && j == t) continue;
					ans += 1ll * c[i][j] * c[k][t];
				}
			}	
		}
	}
	for (int i = 9; i < M; i++) {
		for (int j = 9; j < M; j++) {
			if(c[i][j]) {
				ans += 1ll * c[i][j] * (c[i][j] - 1);
			}
		}
	}
	print(ans / 2);

	return 0;
}



























Measured memory_bytes: 5608