1021

 1 #include <iostream>
 2 #include <iomanip>
 3 #include <cmath>
 4 using namespace std;
 5 int main()
 6  {float a,x0,x1;
 7   cin>>a; 
 8   x0=a/2;
 9   x1=(x0+a/x0)/2;
10   do
11     {x0=x1;
12      x1=(x0+a/x0)/2;
13      }
14   while(fabs(x0-x1)>=1e-5);
15   cout<<setiosflags(ios::fixed)<<setprecision(3)<<x1<<endl;
16   return 0;
17 }