#include<bits/stdc++.h>
using namespace std;
int main(){
	double ans;
    int a; 
	cin>>a;
	if(a<=150){
		cout<<ans*0.4463;
	}else if(a>150&&a<=400){
		ans+=150.0*0.4463+(a-150)*0.4663;
	}else{
		ans+=150.0*0.4463+250*0.4663+(a-400)*0.5663;
	}
	cout<<setprecision(1)<<fixed<<ans;
	return 0;
}