#include <bits/stdc++.h>
using namespace std;
int main()
{
	int a; 
	cin>>a;
	if(0<a and a<150)
	{
		cout<<fixed<<setprecision(1)<<a*0.4463<<endl;
	}
    else if(151<a and a<400)
	{
		cout<<fixed<<setprecision(1)<<a*0.4663<<endl;
	}
	else
	{
		cout<<fixed<<setprecision(1)<<a*0.5663<<endl;
	}
	return 0;	
}