include

include

using namespace std; int main(void){

//freopen("1123.in","r",stdin);
//freopen("1123.out","w",stdout);
int have;
double money;
scanf("%d",&have);
if(have>=0&&have<=150){
	money=have*0.4463;
}else if(have>=151&&have<=400){
	money=150*0.4463+(have-150)*0.4663;
}else{
	money=150*0.4463+(400-150)*0.4663+(have-400)*0.5663;
}
printf("%.1lf",money);
return 0;

}