#include<iostream>
#include<iomanip>
using namespace std;
double n,sum;
int f;
int main(){
	cin>>n;
	if(n<=150) sum = n*0.4463;
	if(n>=151&&n<=400) sum = 66.945+(n-150)*0.4663;
	if(n>=401) sum = 183.0537+(n-400)*0.5663; 
	cout<<fixed<<setprecision(1)<<sum<<endl;
	return 0;
}