#include<iostream>

using namespace std;

float f(float x)
{ return x*x*x+x-1;
}

float DEI(float s, float d)
{
   if(d-s<=0.0001) return s;
   else
   { float m=(s+d)/2;
     if(f(m)==0) return m;
     else if(f(m)<0) return DEI(m,d);
          else return DEI(s,m);   
   }
}  

int main()
{ cout<<DEI(0,1);
  system("pause");
  return 0;
}