#include<bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pii pair<int,int>
using namespace std;
const int N=2e5+10;
const ll M=1e9;
double a[N];
ll num[22][22],ans=0;
int main()
{
	int n;
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
	{
		scanf("%lf",&a[i]);
		ll t=a[i]*M+0.1,cnt2=0,cnt5=0;
		while(t%2==0&&cnt2<=18)t/=2,cnt2++;
		while(t%5==0&&cnt5<=18)t/=5,cnt5++;
		int n2=max(0LL,18-cnt2),n5=max(0LL,18-cnt5);
		for(int j=n2;j<=20;j++)
		for(int k=n5;k<=20;k++)
		ans+=num[j][k];
		num[cnt2][cnt5]++;
	}
	printf("%lld\n",ans);

	return 0;
}
