#include<stdio.h>

int main()
{
	int a;
	double b, c, d;
	scanf("%d", &a);
	if (a>=0&&a <= 150) {
		b = a * 0.4463;
		printf("%.1lf", b);
	}
	else if ("a>150&&a<=400") {
		c = 66.945 + (a - 150.0) * 0.4663;
		printf("%.1lf", c);
	}
	else if (a > 400&&a<10000) {
		d = 183.52 + (a - 400.0) * 0.5663;
		printf("%.1lf", d);
	}
	return 0;
}