include <stdio.h>

int main() {

double c;
int a;
scanf("%d",&a);

if(a<=150)
{
	c=a*0.4463;
}
else if(a>150&&a<=400)
{
	c=150*0.4463+(a-150)*0.4663;
}
else
{
	c=150*0.4463+(400-150)*0.4663+(a-400)*0.5663;
}
printf("%.1lf",c);
return 0;