#include <stdio.h>
#define PI 3.1415926535897932384626433832795

int main(void)
{
	double eps, arg, sign;
  scanf("%lf",&eps);
	while(scanf("%lf",&arg)==1)
	{
    sign=1;
		while(arg>2*PI) arg-=2*PI;
		while(arg<0) arg+=2*PI;
    if(arg>=PI) 
    {
      sign=-1;
      arg-=PI;
    }
    if(arg>=PI/2) arg=PI-arg;
    
    double value=arg, sl=arg;
    long step=1;
    while(sl>eps || sl<-eps)
    {
      sl*=-arg*arg/((step+1)*(step+2));
      step+=2;
      value+=sl;
    }
     printf("%.10g\n", value*sign);
  }
}