#include<bits/stdc++.h>
using namespace std;
int main()
{
	long double a,sum=0;
	cin>>a; 
	if(a<=150)
	{
		sum=a*0.4463;
	}
	if(a>150&&a<=400)
	{
		sum=150*0.4463+(a-150)*0.4663;
	}
	if(a>400)
	{
		sum=150*0.4463+150*0.4663+(a-400)*0.5663;
	}
	cout<<fixed<<setprecision(1)<<sum;
	return 0;
}