#ifdef __CLING__
R__LOAD_LIBRARY(libDelphes)
#include "classes/DelphesClasses.h"
#include "external/ExRootAnalysis/ExRootTreeReader.h"
#endif

//------------------------------------------------------------------------------

void SampleMacro(const char *inputFile0,const char *inputFile1){

  gSystem->Load("libDelphes");  

  TCanvas *c1 = new TCanvas("Photon Contour");
  c1->Divide(2,1);

  const char *name[2] = {"Signal", "Background"};

  TH2F *histPhotonD[2];

  const char *inputFiles[2] = {inputFile0, inputFile1};

  for(int nfile=0; nfile<2; nfile++){

  // Create chain of root trees
  TChain chain("Delphes");
  chain.Add(inputFile);
  
  // Create object of class ExRootTreeReader
  ExRootTreeReader *treeReader = new ExRootTreeReader(&chain);
  Long64_t numberOfEntries = treeReader->GetEntries();
  
  // Get pointers to branches used in this analysis
  TClonesArray *branchPhoton = treeReader->UseBranch("Photon");  

  // Book histograms
   histPhotonD[nfile]= new TH2F(TString::Format("contour_%d", nfile),"", 50,-2.5,2.5,50,-3,3);
   histPhotonD[nfile]->SetStats(0);
   histPhotonD[nfile]->SetTitle(name[nfile]);

   Photon *photon;

  // Loop over all events
  for(Int_t entry = 0; entry < numberOfEntries; ++entry)
  {
    // Load selected branches with data from specified event
    treeReader->ReadEntry(entry);
  
    // If event contains at least 1 photon
    if(branchPhoton->GetEntries() > 0)
    {
      // Take first photon
      photon = (Photon*) branchPhoton->At(0);
      
      histPhotonD[nfile]->Fill(photon->Eta,photon->Phi);
     }
   }
    }// number loop


c1->cd(1);
histPhotonD[0]->Draw("CONT4Z");

c1->cd(2);
histPhotonD[1]->Draw("CONT4Z");
}