//void b2style_pad()

  const int    belle2_font = 133;
const double belle2_tsize = 26;

void set_style()
{
  gROOT->SetStyle("Modern");
  TStyle *belle2Style = new TStyle("BelleII","Belle II style");
  
  // set the paper & margin sizes
  belle2Style->SetPaperSize(20,26);
  
  // set canvas, pads, etc.
  //belle2Style->SetCanvasDefW(600);
  //belle2Style->SetCanvasDefH(600);
  //belle2Style->SetCanvasDefW(600);
  //belle2Style->SetCanvasDefH(600);
  
  belle2Style->SetFillColor(1);
  belle2Style->SetFillStyle(1001);
  belle2Style->SetFrameFillColor(0);
  belle2Style->SetFrameBorderMode(0);
  belle2Style->SetPadBorderMode(0);
  belle2Style->SetPadColor(0);
  belle2Style->SetCanvasBorderMode(0);
  belle2Style->SetCanvasColor(0);
  belle2Style->SetStatColor(0);
  belle2Style->SetLegendBorderSize(0);

   // set margin sizes
  belle2Style->SetPadTopMargin(0.05);
  belle2Style->SetPadRightMargin(0.05);
  belle2Style->SetPadBottomMargin(0.16);
  belle2Style->SetPadLeftMargin(0.16);
  
  // use large fonts
  belle2Style->SetTextFont(belle2_font);
  belle2Style->SetTextSize(belle2_tsize);
  
  belle2Style->SetLabelFont(belle2_font,"x");
  belle2Style->SetTitleFont(belle2_font,"x");
  belle2Style->SetLabelFont(belle2_font,"y");
  belle2Style->SetTitleFont(belle2_font,"y");
  belle2Style->SetLabelFont(belle2_font,"z");
  belle2Style->SetTitleFont(belle2_font,"z");
  
  belle2Style->SetLabelSize(belle2_tsize,"x");
  belle2Style->SetLabelSize(belle2_tsize,"y");
  belle2Style->SetLabelSize(belle2_tsize,"z");
  belle2Style->SetTitleSize(belle2_tsize,"x");
  belle2Style->SetTitleSize(belle2_tsize,"y");
  belle2Style->SetTitleSize(belle2_tsize,"z");
  
  belle2Style->SetTitleOffset(1.5,"x");
  belle2Style->SetTitleOffset(1.5,"y");
  belle2Style->SetTitleOffset(1.5,"z");
  
  belle2Style->SetLabelOffset(0.01,"x");
  belle2Style->SetLabelOffset(0.01,"y");
  belle2Style->SetLabelOffset(0.01,"z");
  
  belle2Style->SetLegendFont(belle2_font);

   // use bold lines and markers
  belle2Style->SetMarkerStyle(20);
  belle2Style->SetMarkerSize(1.0);
  belle2Style->SetHistLineWidth(2);
  belle2Style->SetFrameLineWidth(2);
  belle2Style->SetLineWidth(2);
  belle2Style->SetFuncWidth(2);
  belle2Style->SetLineStyleString(2,"[12 12]");// postscript dashes
  
  // get rid of X error bars
  //belle2Style->SetErrorX(0.001);
   // get rid of error bar caps
  belle2Style->SetEndErrorSize(0.);
  
  // do not display any of the standard histogram decorations
  belle2Style->SetOptTitle(0);
  belle2Style->SetOptStat(0);
  belle2Style->SetOptFit(0);
  
  // put tick marks on top and RHS of plots
  belle2Style->SetPadTickX(1);
  belle2Style->SetPadTickY(1);
  
  // histogram divisions: only 5 in x to avoid label overlaps
  belle2Style->SetNdivisions(505,"x");
  belle2Style->SetNdivisions(510,"y");
  
  // function
  belle2Style->SetFuncColor(kBlue);
  belle2Style->SetFuncStyle(0);
  
  // legend
  belle2Style->SetLegendBorderSize(0);
  belle2Style->SetLegendFillColor(0);
  
  belle2Style->SetHistMinimumZero();
  
  std::cout << "-------------------------" << std::endl;
  std::cout << "Set Belle II Style" << std::endl;
  std::cout << "-------------------------" << std::endl;
   
  gROOT->SetStyle("BelleII");
  gROOT->ForceStyle();
  
  TGaxis::SetMaxDigits(4);
}
void b2_style_pad()
    
{
  TCanvas *c1 = new TCanvas("c1", "c1",900,900);
  //gStyle->SetOptStat(0);
  
  // Create the three pads
  TPad *center_pad = new TPad("center_pad", "center_pad",0.0,0.0,0.6,0.6);
  center_pad->Draw();
  
  right_pad = new TPad("right_pad", "right_pad",0.55,0.0,1.0,0.6);
  right_pad->Draw();
  
  top_pad = new TPad("top_pad", "top_pad",0.0,0.55,0.6,1.0);
  top_pad->Draw();
  
  // Create, fill and project a 2D histogram.
  TH2F *h1 = new TH2F("ks_fde","",100, -50,400,100,-50,400);
  TH2F *h2 = new TH2F("ks_fde_sig","",100, -50,400,100,-50,400);
  //TH1F *h3 = new TH1F("ksa_fde_sig","",100, -50,400);
  //TH1F *h4 = new TH1F("ksb_fde_sig","",100, -50,400);
  TLine *l1 = new TLine(20,0,20,1720);
  TLine *l2 = new TLine(20,0,20,1055);

  TFile *f = new TFile("for_fds_plots.root");
  TTree *tree = (TTree*)f->Get("DstD0PiKSKS");
  
  Double_t  KS1_flightDistance, KS1_flightDistanceErr,KS2_flightDistance, KS2_flightDistanceErr, Dst_isSignalAcceptMissingGamma, KS1_mcFlightDistance, KS2_mcFlightDistance;
     
  tree->SetBranchAddress("KS1_flightDistance",&KS1_flightDistance);
  tree->SetBranchAddress("KS2_flightDistance",&KS2_flightDistance);
  tree->SetBranchAddress("KS1_flightDistanceErr",&KS1_flightDistanceErr);
  tree->SetBranchAddress("KS2_flightDistanceErr",&KS2_flightDistanceErr);
  tree->SetBranchAddress("Dst_isSignalAcceptMissingGamma",&Dst_isSignalAcceptMissingGamma);

  Int_t nentries = (Int_t)tree->GetEntries();
  for (Int_t i=0; i<nentries; i++) {
    tree->GetEntry(i);    
    h1->Fill(KS1_flightDistance/(KS1_flightDistanceErr),KS2_flightDistance/(KS2_flightDistanceErr));
    //h1->SetMarkerColor("kBlue");
    //h1->SetMarkerStyle("24");
    h1->GetXaxis()->SetTitle("flight distance significance (lower momentum K^{0}_{S})");
    h1->GetXaxis()->SetTitleSize(0.05);
    h1->GetYaxis()->SetTitle("flight distance significance (higher momentum K^{0}_{S})");
    h1->GetYaxis()->SetTitleSize(0.04);
    h1->GetYaxis()->SetTitleOffset(1);
    
    if(Dst_isSignalAcceptMissingGamma==1){
      h2->Fill(KS1_flightDistance/(KS1_flightDistanceErr),KS2_flightDistance/(KS2_flightDistanceErr));
      //h2->SetMarkerColor("kRed");
      //h2->SetMarkerStyle("7");
      
    }
  }

  TH1D * projh2X = h1->ProjectionX();
  TH1D * projh2Y = h1->ProjectionY();
  TH1D * projh2X_sig = h2->ProjectionX();
  TH1D * projh2Y_sig = h2->ProjectionY();  
  
  // Drawing
  center_pad->cd();
  gStyle->SetPalette(1);
  h1->Draw();
      
  h2->Draw("same");

  top_pad->cd();
  projh2X->SetLineColor(kBlue);
  projh2X->SetLineWidth(2);
  projh2X->Draw("");
  projh2X_sig->Scale(50);
  projh2X_sig->SetLineColor(kRed);
  projh2X_sig->SetLineWidth(2);
  projh2X_sig->Draw("same");
  l1->Draw("same");
  l1->SetLineWidth(2);
  l1->SetLineStyle(2); 
  
    
  right_pad->cd();
  projh2Y->SetLineColor(4);
  projh2Y->SetFillStyle(0);
  projh2Y->SetLineStyle(1);
  projh2Y->SetLineWidth(2);
  projh2Y->Draw("");
  projh2Y_sig->Scale(50);
  projh2Y_sig->SetLineColor(kRed);
  projh2Y_sig->SetLineStyle(1);
  projh2Y_sig->SetLineWidth(2);
  //sprojh2Y_sig->Draw("");
  projh2Y_sig->Draw("same");
  l2->Draw("same");
  l2->SetLineWidth(2);
  l2->SetLineStyle(2); 

  set_style(); 

  c1->cd();
  c1->cd();
  auto logo = new TLatex();
  TLatex *logo = new TLatex();
  //logo->SetNDC();
  //logo->SetTextSize(belle2_tsize);
  logo->DrawLatex(0.66,0.90, "#bf{#it{Belle II}} simulation");
  logo->DrawLatex(0.64,0.84, " #it{#scale[0.6]{#int} L dt} = 70 fb^{#minus1}");
  logo->DrawLatex(0.65,0.78,"#it{D}^{0}#rightarrow#it{K}^{0}_{S}#it{K}^{0}_{S}");

  TLegend *legend = new TLegend(.75,.80,.95,.95);
  legend->AddEntry( projh2X_sig,"Signal  X50");
  //legend->AddEntry(h2,"Signal");
  legend->AddEntry( projh2X,"Total");
  legend->AddEntry(l1," > 20","l");
  legend->Draw();
    
}