{

 TFile f("working_dir_KpKm_invMass_mixedEvents_63GeV/mixedEvents.root"); 
 f.ls();

 TCanvas *c1 = new TCanvas("c1","c1",400,250,899,699);
 c1->Range(-12, -12, 12, 12);
 c1->SetBorderSize(2);
 c1->SetFrameFillColor(0);

 TTree* t = (TTree*) f.Get("invMass");
 //t->StartViewer();

 char str[200];

 Int_t filterNumber;
 TNtuple* ntpl = new TNtuple();

 t->SetBranchAddress("FilterNumberBranch",  &filterNumber);
 t->SetBranchAddress("InvMassNTupleBranch", &ntpl);
 
 Int_t numberOfFilters = TMath::Nint(t->GetEntries());

 cout<<endl
      <<"Number of filters =  "<<numberOfFilters<<endl
      <<endl;

 for(Int_t fn=0; fn<numberOfFilters; fn++)
 {
         t->GetEntry(fn);

         if(TMath::Nint(ntpl->GetEntries())==0) continue;

         ntpl->Draw(Form("invMass>>htemp%i",fn), "", "");
         TH1F* htemp = (TH1F*) gDirectory->Get(Form("htemp%i",fn));
         cout<<"htemp = "<<htemp<<endl;
         sprintf(str, "invMassHist%06i", fn);
         htemp->SetNameTitle(str, "K^{+}K^{-} invariant mass: Phobos PR04 (63 GeV mixed events)");
         htemp->SetFillColor(5); // yellow
         c1->Update();
         sprintf(str, "KpKmInvMass_mixedEvents_63GeV_filter%06i.gif", fn); c1->SaveAs(str);
         sprintf(str, "KpKmInvMass_mixedEvents_63GeV_filter%06i.root", fn); c1->SaveAs(str);

 }// end of for

 delete ntpl;

}