#include <iostream>
using namespace std;
float f(float x) {return x*x-2;}

int main()
{ float a=1, b=2, c,fa,fb,fc,eps=0.000001;
  fa=f(a);
  fb=f(b);
  while (eps < b-a)
  { c=(a+b)/2;
    fc=f(c);
    if (fc==0) {cout<<c<<endl; return 0;}
    else if (fc*fa>0) {a=c;}
         else         {b=c;}
  }
  cout<<c<<endl;
  return 0;
}