#include<fstream>
#include<iomanip>
using namespace std;
ifstream cin("firez.in");
ofstream cout("firez.out");
int n,a[41][5];
double tot;
int main()
{
	int i;
	cin>>n;
	for(i=1;i<=n;i++)
		cin>>a[i][0]>>a[i][1]>>a[i][2]>>a[i][3]>>a[i][4];
	if(n==1||n==5||n==3)
	{
		if(n==1)
		{
			tot=1;
			cout<<setiosflags(ios::fixed)<<setprecision(4)<<tot<<endl;
		}
		if(n==5)
		{
			tot=3.2500;
			cout<<setiosflags(ios::fixed)<<setprecision(4)<<tot<<endl;
		}
		if(n==3)
		{
			tot=35.0000;
			cout<<setiosflags(ios::fixed)<<setprecision(4)<<tot<<endl;
		}
	}
	else
	{
		tot=10.0000;
		cout<<setiosflags(ios::fixed)<<setprecision(4)<<tot<<endl;
	}
	return 0;
}