#include
int main ()
{double x,y=0,t;
int i;
scanf("%lf",&x);
t=x;
x*=x;
for(i=1;t>=1e-7;i+=2)
{if(i%4==1)y+=t;
else y-=t;
t=t*x/((i+1)*(i+2));
}
printf("%lf\n",y);
return 0;
}
#include
int main ()
{double x,y=0,t;
int i;
scanf("%lf",&x);
t=x;
x*=x;
for(i=1;t>=1e-7;i+=2)
{if(i%4==1)y+=t;
else y-=t;
t=t*x/((i+1)*(i+2));
}
printf("%lf\n",y);
return 0;
}
