#include  <iostream>
using namespace std;
int main()
{
	double a,b=0,c,d,e,f,g,h,i;
	int o;
	cin>>a;
		if(a<=150){
			b=a*0.4463;
		}
		else{
			if(a>150 && a<401){
				c=a-150;
				a=a-c;
				b=a*0.4463+c*0.4663;
			}
			else{
				c=a-150-(401-150);
				d=a-c-150;
				a=a-c-d;
				b=d*0.4663+a*0.4463+c*0.5663;
			}
		}
	b=b*10;
	o=b;
	b=o*0.1;
	cout<<b;
	return 0;
 }