#include <iostream>
#include <cmath>
using namespace std;
float f (float x) {return x*x-2;}
float f1(float x) {return 2*x;}
int main()
{ float x=1, fx=f(x), eps=0.000001;
  while (eps < fabs(fx))
  { x=x-fx/f1(x);
        fx=f(x);
  }
  cout<<x<<endl;
  return 0;
}