{
   TCanvas *c1 = new TCanvas("c1","transparent pad");
   TPad *pad1 = new TPad("pad1","",0,0,1,1);
   TPad *pad2 = new TPad("pad2","",0,0,1,1);
   pad2->SetFillStyle(4000); //will be transparent
   c1->SetBorderMode(0);
   c1->SetBorderSize(2);
   pad1->SetBottomMargin(0.14);
   pad1->Draw();
   pad1->cd();

   TGraphErrors *gre = new TGraphErrors(1);
   gre->SetName("Graph");
   gre->SetTitle("");
   gre->SetFillColor(1);
   gre->SetLineWidth(2);
   gre->SetMarkerStyle(20);
   gre->SetMarkerSize(0.7);
   gre->SetPoint(0,30,0.04863153);
   gre->SetPointError(0,0,0.003806435);
   gre->Draw("AP");
   gre->GetXaxis()->SetTitle("Z");
   gre->GetYaxis()->SetTitle("Y(Z)");
   gre->GetXaxis()->CenterTitle(true);
   gre->GetYaxis()->CenterTitle(true);
   pad1->Update();
   pad1->Modified();
   c1->cd();

  TGraphErrors *greNoZ = new TGraphErrors(1);
   greNoZ->SetName("greNoZ");
   greNoZ->SetTitle("");
   greNoZ->SetFillColor(1);
   greNoZ->SetLineWidth(2);
   greNoZ->SetMarkerStyle(20);
   greNoZ->SetMarkerSize(0.7);
   greNoZ->SetPoint(0,30,1.484217);
   greNoZ->SetPointError(0,0,0.0108437);

   //compute the pad range with suitable margins
   Double_t ymin = 1.35;
   Double_t ymax = 1.55;
   Double_t dy = (ymax-ymin)/0.84; //10 per cent margins top and bottom
   // Double_t dy = (ymax-ymin)/0.8; //10 per cent margins top and bottom
   Double_t xmin = 29.9;
   Double_t xmax = 31.1;
   Double_t dx = (xmax-xmin)/0.73; //10 per cent margins left and right
   // Double_t dx = (xmax-xmin)/0.8; //10 per cent margins left and right
   // pad2->Range(xmin-0.1*dx,ymin-0.1*dy,xmax+0.1*dx,ymax+0.1*dy);
   pad2->Range(xmin-0.12*dx,ymin-0.14*dy,xmax+0.15*dx,ymax+0.02*dy);
   pad2->SetBottomMargin(0.14);
   pad2->Draw();
   pad2->cd();
   greNoZ->SetLineColor(kRed);
   greNoZ->SetMarkerColor(kRed);
   greNoZ->GetYaxis()->SetTitle("<N>/Z");
   greNoZ->GetYaxis()->SetTitleSize(0.07);
   greNoZ->Draw("LP");
   pad2->Update();

   // draw axis on the right side of the pad
   TGaxis *axis = new TGaxis(xmax,ymin,xmax,ymax,ymin,ymax,5,"+L");
   axis->SetLabelColor(kRed);
   axis->SetTitleColor(kRed);
   axis->SetLabelSize(0.06);
   axis->SetTitleFont(42);
   axis->SetTitleOffset(0.9);
   axis->SetTitle("<N>/Z");
   axis->CenterTitle(true);
   axis->SetTitleSize(0.07);
   axis->Draw();
}