> #include<iostream>
> #include<iomanip>
> #include<cmath>
> using namespace std;
> int main()
> {
> 	double R[1000],r; int n[1000],i;
> 	const double pi=3.14159265358979323846264338327950288;
>     　　　int N;
> 	cin>>N;
> 	for(i=1;i<=N;i++)cin>>R[i]>>n[i];
> 	for(i=1;i<=N;i++)
> 	{
> 		r=(1-1/(1+sin(pi/n[i])))*R[i];
>         cout<<"Scenario #"<<i<<":"<<endl;
> 		cout<<setiosflags(ios::fixed)<<setprecision(3);
> 		cout<<r<<endl;
> 		cout<<endl;
> 	}
> 	return 1;
> }