#include<bits/stdc++.h>
using namespace std;
int main(){
	int a;
	double f=0;
	cin>>a;
	if(a<=150){
		f+=a*0.4463;
	}
	if(a>150&&a<=400){
		f+=(a-150)*0.4663;
	}
	if(a>400&&a<=400){
		f+=(a-150-400)*0.5663;
	}
	printf("%.1f",f);
}