#include<vector>
#include<set>
#include<map>
#include<queue>
#include<string>
#include<algorithm>
#include<iostream>
#include<bitset>
#include<functional>
#include<numeric>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cassert>
#include<cmath>
#include<iomanip>
#include<random>
#include<ctime>
#include<complex>
using namespace std;
typedef long long LL;
typedef double D;
#define all(v) (v).begin(), (v).end()
mt19937 gene(233);
typedef complex<double> Complex;
#define fi first
#define se second
#define ins insert
#define pb push_back
inline char GET_CHAR(){
	const int maxn = 131072;
	static char buf[maxn],*p1=buf,*p2=buf;
	return p1==p2&&(p2=(p1=buf)+fread(buf,1,maxn,stdin),p1==p2)?EOF:*p1++;
}
inline int getInt() {
	int res(0);
	char c = getchar();
	while(c < '0') c = getchar();
	while(c >= '0') {
		res = res * 10 + (c - '0');
		c = getchar();
	}
	return res;
}

inline LL fastpo(LL x, LL n, LL mod) {
	LL res(1);
	while(n) {
		if(n & 1) {
			res = res * (LL)x % mod;
		}
		x = x * (LL) x % mod;
		n /= 2;
	}
	return res;
}
LL gcd(LL a, LL b) { return b ? gcd(b, a % b) : a; }

inline string itoa(int x, int width = 0) {
  string res;
  if(x == 0) res.push_back('0');
  while(x) {
    res.push_back('0' + x % 10);
    x /= 10;
  }
  while((int)res.size() < width) res.push_back('0');
  reverse(res.begin(), res.end());
  return res;
}
const int _B = 131072;
char buf[_B];
int _bl = 0;
inline void flush() {
	fwrite(buf, 1, _bl, stdout);
	_bl = 0;
}
__inline void _putchar(char c) {
	if(_bl == _B) flush();
	buf[_bl++] = c;
}
inline void print(LL x, char c) {
	static char tmp[20];
	int l = 0;
	if(!x) tmp[l++] = '0';
	else {
		while(x) {
			tmp[l++] = x % 10 + '0';
			x /= 10;
		}
	}
	for(int i = l - 1; i >= 0; i--) _putchar(tmp[i]);
	_putchar(c);
}
struct P {
	D x, y;
};
const int N = 300033;
const int LOG = 20;
const int mod = 1e9 + 7;
const int inf = 1e9 + 7;
int n, m;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
const int _ = 50;
int cnt[111][111], s[111][111];
int main() {
	int n;
	cin >> n;
	LL ans = 0;
	for(int i = 0; i < n; i++) {
		string t;
		cin >> t;
		LL a, b;
		if(find(all(t), '.') == t.end()) {
			int x;
			sscanf(t.c_str(), "%d", &x);
			a = x;
			b = 1;
		}else {
			int pos = t.size() - 1 - (find(all(t), '.') - t.begin());
			b = 1;
			while(pos) {
				b *= 10;
				pos--;
			}
			t.erase(find(all(t), '.'));
			//cout << t << endl;
			a = 0;
			for(char c : t) {
				a = a * 10 + c - '0';

			}
		}
		//cout << a << ' ' << b << endl;
		
		LL d = gcd(a, b);
		a /= d;
		b /= d;
		if(b == 1) ans--;
		int cnt2 = 0;
		//cout << a << ' ' << b << endl;
		while(b % 2 == 0) {
			cnt2 --;
			b /= 2;
		}
		while(a % 2 == 0) {
			cnt2++;
			a /= 2;
		}
		int cnt5 = 0;
		while(b % 5 == 0) {
			cnt5 --;
			b /= 5;
		}
		while(a % 5 == 0) {
			cnt5++;
			a /= 5;
		}
		cnt[cnt2 + _][cnt5 + _]++;
		//cout << cnt2 << ' ' << cnt5 << endl;
	}
	for(int i = _ * 2; i >= 0; i--) {
		for(int j = _ * 2; j >= 0; j--) {
			int sum = cnt[i][j];
			if(i < _ * 2) sum += s[i + 1][j];
			if(j < _ * 2) sum += s[i][j + 1];
			if(i < _ * 2 && j < _ * 2) sum -= s[i + 1][j + 1];
			s[i][j] = sum;
		}
	}
	for(int i = _ * 2; i >= 0; i--) {
		for(int j = _ * 2; j >= 0; j--) {
			ans += cnt[i][j] * (LL)s[2 * _ - i][2 * _ - j];
		}
	}
	cout << ans / 2 << endl;
}






Measured memory_bytes: 3732