#include<stdio.h>
int main()
{
	float price = 0; 
	scanf("%f", &price);  
	if (price >= 100 && price <=499)
	{
		price  *= 0.9; 
	}
	else if (price >= 500 && price <= 1999)
	{
		price  *= 0.8; 
	}
	else if (price >= 2000 && price <= 4999)
	{
		price  *= 0.7;  
	}
	else
	{
		price *= 0.6; 
	}
	printf("%.1f", (float)price); 
	return 0; 
}