include[HTML_REMOVED]

using namespace std;

const double eps=1e-8;

int main()
{
double n;
cin>>n;
double l=-100,r=100;
while(r-l>eps)
{
double m=l+(r-l)/2;
if(mmm>n)
{
r=m;
}
else
{
l=m;
}
}
printf(“%.6f\n”,l);
return 0;
}