/********************** STEP 3 **********************/
  cout<<"Step 3: The actual survival probability is defined as the product of the reactor antineutrino energy spectrum (the reactor function) and the survival probability function."<<endl; 
  cout<<"Plot the survival probability function for the near and the far detector."<<endl; 
  cout<<"Do they agree with your expectations? What does happen if you change the near and the far distances? What is the optimal choice?"<<endl<<endl<<endl; 

  //Once dNear has been set, comment the line below
  return;

  //Near detector
  //Set the distance for the near detector in km
  double dNear;//= ---write-value-here---; //km -- set here the distance to the near detector
  oscil->SetParameter(0,dNear);
  
  TF1 *near=new TF1("near","reactor*oscil",0.,10.);
  near->SetLineColor(kRed);
  near->SetTitle("Spectrum; E [MeV]; expected flux");
  near->SetMinimum(0.); near->SetMaximum(0.25);

  oscil->SetParameter(0,dFar);
  TF1 *far=new TF1("far","reactor*oscil",0.,10.);
  far->SetLineColor(kBlue);

  //Draw the functions
  reactor->SetLineColor(kBlack); reactor->SetLineStyle(4);
  near->SetNpx(300); far->SetNpx(300);
  TCanvas *functions=new TCanvas();
  near->Draw(); far->Draw("same"); reactor->Draw("same");
  return;
  //comment '//' the 3 lines above to proceed with the exercise


  cout<<"We can now calculate the numbers of events in each spectrum (using the function Integral)"<<endl;
  cout<<"What would be the minimum value of energy, x, to calculate your integral?"<<endl;

  //Once x has been set, comment the line below
  return;
  
  //Substitute x with the value of the energy's threshold
  double x;//= ---write-value-here--- ; //MeV
  double nearVisibleFraction = near->Integral(x,8.2);
  double farVisibleFraction = far->Integral(x,8.2);

  cout<<"Fraction of ND events "<<nearVisibleFraction <<endl;
  cout<<"Fraction of FD events "<<farVisibleFraction<<endl<<endl<<endl;

  //Comment the following line and paste STEP 4 to proceed with the exercise
  return;