include <stdio.h>

int main() {

double n,a,b,c,d,e,f,g;
scanf("%lf",&n);
if(n<=150)
{
	a=n*0.4463;
	printf("%.1lf",a);
}
if(n>150&&n<=400)
{
	b=(n-150)*0.4663;
	c=150*0.4463+b;
	printf("%.1lf",c);
}	
if(n>400)
{
	d=(n-400)*0.5663;
	e=(400-150)*0.4663;
	f=150*0.4463;
	g=d+e+f;
	printf("%.1lf",g);
}

return 0;

}