void calbet2(){

   TH1::SetDefaultSumw2;

   gStyle->SetOptTitle(1); // set hist title
   gStyle->SetTitleSize(0.05, "t");
   gStyle->SetTitleX(0.4); //title X location
   gStyle->SetTitleY(0.9); //title Y location
   gStyle->SetTitleW(0.5); //title width
   gStyle->SetTitleH(0.15); //title height

   // input file
   auto file = new TFile ("hist-mc16_13TeV.root");
   if ( !file->IsOpen() ) printf("File no found!!\n");

   string dir                    {"MediumLLH_Smooth_v11/MediumLLH_Smooth_v11_"};
   const vector<string> v_temp   {"tempFailedLoose"};
   const vector<string> v_region {"peak", "tail"};
   const vector<string> v_eta    {"barrel", "endcap"};
   const vector<string> v_pt     {"l0-20", "20-25", "25-40", "gt40"};

   string name;

   const int ntemp   = v_temp.size();
   const int nregion = v_region.size();
   const int neta    = v_eta.size();
   const int npt     = v_pt.size();

   TH1D * templates   [ntemp][nregion][neta][npt];
   TH1D * templates_norev[ntemp][nregion][neta][npt];

   for (int temp = 0; temp < ntemp; temp++) {
      for (int region = 0; region < nregion; region++) {
         for (int eta = 0; eta < neta; eta++) {
            for (int pt = 0; pt < npt; pt++) {
               name = dir + v_temp[temp] + "_" + v_region[region] + "_" + v_eta[eta] + "_" + v_pt[pt];
               templates[temp][region][eta][pt] = (TH1D*)file -> Get(name.c_str());
               name = dir + v_temp[temp] + "_norev_" + v_region[region] + "_" + v_eta[eta] + "_" + v_pt[pt];
               templates_norev[temp][region][eta][pt] = (TH1D*)file -> Get(name.c_str());
            } // pt
         } // eta
      } // region
   } // temp

   TCanvas *canvas[3];
   for (int temp = 0; temp < ntemp; temp++) {
      name         = v_temp[temp];
      canvas[temp] = new TCanvas (name.c_str(), name.c_str(), 1300, 790);
      canvas[temp]->Divide(4, 2);
   }

   auto legend = new TLegend(0.2, 0.1, 0.9, 0.9);
   legend->SetTextSize(0.04);
   legend->SetTextFont(102);

   double scale[3][0][2][4]{};

   for (int temp = 0; temp < ntemp; temp++) {
      for (int eta = 0; eta < neta; eta++) {
         for (int pt = 0; pt < npt; pt++) {
            double num = templates      [temp][1][eta][pt] -> Integral();
            double den = templates_norev[temp][1][eta][pt] -> Integral();
            double scale{1};
            if (den != 0) scale = num / den;
            templates_norev[temp][0][eta][pt] -> Scale(scale);
            if (temp == 0) {
               int pad = 4*eta + pt + 1;
               canvas[temp] -> cd(pad);
               name = v_pt[pt] + " ; " + v_eta[eta];
               double maxhist = std::max(templates[temp][0][eta][pt] -> GetMaximum(), templates_norev[temp][0][eta][pt] -> GetMaximum());

               templates      [temp][0][eta][pt] -> SetLineColor(kRed);
               templates      [temp][0][eta][pt] -> SetTitle(name.c_str());
               templates      [temp][0][eta][pt] -> GetXaxis() -> SetTitle("E_{T}^{cone0.3}/25 GeV");
               templates      [temp][0][eta][pt] -> GetYaxis() -> SetTitle("Entries");
               templates      [temp][0][eta][pt] -> GetYaxis() -> SetRangeUser(0, maxhist + maxhist*0.2);
               templates      [temp][0][eta][pt] -> Draw();
               templates_norev[temp][0][eta][pt] -> SetLineColor(kBlue);
               templates_norev[temp][0][eta][pt] -> Draw("same");

//// >>>>>>> problem is here ....
auto ratio = new TRatioPlot(templates[temp][0][eta][pt], templates_norev[temp][0][eta][pt]);
//// <<<<<<<
/*
canvas[temp] -> SetTicks(0, 1);

std::vector<double> lines = {0.8, 1., 1.2};
ratio -> SetGridlines(lines);
ratio -> GetLowerRefGraph() -> SetMinimum(-1);
ratio -> GetLowerRefGraph() -> SetMaximum(2);
ratio -> Draw("same");    ///// <<<<<<<<<<<<<<< Where do you draw the ratio plot ?? it cannot be drawn in a divided canvas
canvas[temp] -> Update();
*/
            } // template failed loose
         } // pt
      } // eta
   } // temp
}