#ifdef __CLING__
R__LOAD_LIBRARY(libDelphes)
#include "classes/DelphesClasses.h"
#include "external/ExRootAnalysis/ExRootTreeReader.h"
#endif
 #define Lumi 100

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

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

   gSystem->Load("libDelphes");  
   TCanvas *c1 = new TCanvas("Lepton_PT");

//   THStack *zPT= new THStack("hs","test stacked histograms");

   TH1 *histPhotonPT[2];

 Double_t sigW = (1.36*Lumi)/50000; Double_t bgW = (2.45*Lumi)/50000;
 Double_t weight[2] = {bgW, sigW};

   //Book Legend
   TLegend *legend1 = new TLegend(0.4,0.2,0.7,0.33);

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

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

  // Create chain of root trees
  TChain chain("Delphes");
  chain.Add(inputFiles[nfile]);
  
  // 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");       //Edited

  // Book histograms
 histPhotonPT[nfile] = new TH1F(TString::Format("zboson_pt_%d", nfile), "(Z-boson)", 100, 0.0, 500.0);

// zPT->Add(histZbosonPT[nfile]);

   histPhotonPT[nfile]->SetLineWidth(2);
   histPhotonPT[nfile]->SetStats(0);
   histPhotonPT[nfile]->GetXaxis()->SetTitle("MP_{Z}(GeV)");
   histPhotonPT[nfile]->GetYaxis()->SetTitle("Number of Events");

   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(branchPhoton->GetEntries() > 0)
    {
      // Take first photon
      photon = (Photon*) branchPhoton->At(0);

      histPhotonPT[nfile]->Fill(photon->PT, weight[nfile]);
     }
}
}

//   c1->SetLogy();
   c1->SetTickx();
   c1->SetTicky();
   c1->SetGrid();

  c1->cd();
   histPhotonPT[0]->SetLineColor(kBlack);
   histPhotonPT[1]->SetLineColor(kRed);
   histPhotonPT[0]->Draw();
   histPhotonPT[1]->Draw("sames");

// zPT->Draw();

  legend1->AddEntry(histPhotonPT[0], "Background","f");
  legend1->AddEntry(histPhotonPT[1], "SP-Type","f");
  legend1->SetTextSize(0.031);
  legend1->Draw();

}