void DrawMassBG(TString nSt="") {

  TStopwatch timer;
  timer.Start();

//  gROOT->LoadMacro("$VMCWORKDIR/gconfig/basiclibs.C");
//  basiclibs();

TStyle *plain = new TStyle("Plain","Plain Style(no colors/fill areas)");
//plain->SetCanvasBorderMode(0);
//plain->SetPadBorderMode(0);
plain->SetPadColor(0);
plain->SetCanvasColor(0);
plain->SetTitleColor(0);
plain->SetStatColor(0);
plain->SetOptStat(110010);
//plain->SetOptStat(1000000000);
plain->SetOptFit(0011);
plain->SetStatW(0.225);
plain->SetStatH(0.06);
//plain->SetStatX(0.7);
plain->SetOptTitle(0);
plain->cd();

  TString name = "out.root";
  TFile *dirOld = new TFile("out_old.root","read");
  TFile *dirNew = new TFile("out_new.root","read");

  TH1D *hMassOld, *hMassNew;
  TF1  *fResOld, *fResNew;
    
  hMassOld = (TH1D*) dirOld->Get("massBG");
  hMassOld->SetLineColor(4);
  hMassNew = (TH1D*) dirNew->Get("massBG");
  hMassNew->SetLineColor(2);
  
  TCanvas *c1;
  c1 = new TCanvas("c1","position",0,0,1200,800);
  //  c1 -> Divide(NParameters-2,2);
  hMassOld->GetXaxis()->SetTitle("Mass BG [GeV/c^{2}]");
  hMassOld->GetXaxis()->SetTitleOffset(1);
  hMassOld->Draw();
  hMassNew->Draw("same");
  
  TLegend *leg = new TLegend(0.5,0.7,0.7,0.9);
  //leg->SetHeader("Legend Title");
  leg->AddEntry(hMassOld,"Old function","l");
  leg->AddEntry(hMassNew,"New function","l");
  leg->SetFillColor(0);
  leg->Draw();

  TCanvas *c2;
  c2 = new TCanvas("c2","position",0,0,1200,800);
  c2 -> Divide(2,1);
  c2->cd(1);
  hMassOld->GetXaxis()->SetTitle("Old Mass BG [GeV/c^{2}]");
  hMassOld->GetXaxis()->SetTitleOffset(1);
  hMassOld->Draw();
  c2->cd(2);
  hMassNew->GetXaxis()->SetTitle("New Mass BG [GeV/c^{2}]");
  hMassNew->GetXaxis()->SetTitleOffset(1);
  hMassNew->Draw();
  
  c1->SaveAs("BGMassComparison.pdf");
  c2->SaveAs("BGMass.pdf");
 
  timer.Stop();
  Double_t rtime = timer.RealTime();
  Double_t ctime = timer.CpuTime();
  printf("RealTime=%f seconds, CpuTime=%f seconds\n",rtime,ctime);

}