#include<bits/stdc++.h>
using namespace std;
double a;
int main(){
	cin>>a;
	if(a<=150)cout<<fixed<<setprecision(1)<<a*0.4463;
	else if(a>=151&&a<=400)cout<<fixed<<setprecision(1)<<150.0*0.4463+(a-150.0)*0.4663;
	else cout<<fixed<<setprecision(1)<<150.0*0.4463+400.0*0.4663+(a-400.0)*0.5663;
return 0;
}