#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
	double a;
	cin>>a;
	if(a<151) cout<<fixed<<setprecision(2)<<a*0.4463;
	else if(a>150 && a<401) cout<<fixed<<setprecision(2)<<a*0.4663;
	else cout<<fixed<<setprecision(2)<<a*0.5663;
}