include[HTML_REMOVED]
include[HTML_REMOVED]
using namespace std;
int main()
{
double x;
cin>>x;
double a=-1,b=1;
double l=min(a,x);
double r=max(b,x);
while(r-l>1e-8)
{
double m=(l+r)/2;
if(mmm>=x) r=m;
else l=m;
}
printf(“%lf”,r);
}