#include

#include

using namespace std;

int main()

{

double n,a,b,c;
cout<<setiosflags(ios::fixed)<<setprecision(1);
cin>>n;

if(n<=150)	
cout<<n*0.4463;
if(150<=n<=400)
cout<<150*0.4463+(n-150)*0.4663;
if(n>400)
cout<<150*0.4463+250*0.4663+(n-400)*0.5663;

}