#include<stdio.h>
int main()
{
	float a = 0, sum = 0;
	scanf("%f", &a);
	if (a >= 100)
	{
		if (a < 500)
			sum = a * 0.9;
		else if (a < 2000)
			sum = a * 0.8;
		else if (a < 5000)
			sum = a * 0.7;
		else sum = a * 0.6;

	}
	printf("%.1f", sum);
	return 0;
}