#include<stdio.h>
main()
{
    int x;
	float y;
    scanf("%d",&x);
	if(x<=150)
	  y=x* 0.4463;
    else if(x>150&&x<=400)
      y=(x-150) *0.4663+150*0.4463;
    else
      y=(x-400) *0.5663+(400-151)*0.4663+150*0.4663;
	printf("%.1f",y); 
}