void Limit(){
 
 c1 = new TCanvas("c1","observe+expected cls",200,10,700,500);
 c1->SetGrid();
 TMultiGraph *mg = new TMultiGraph();

      TH1F *signal=new TH1F("signal","signal",4, 0., 4.);
      TH1F *bkg=new TH1F("bkg","bkg",4, 0., 4.);
      TH1F *data=new TH1F("data","data",4, 0., 4.);      

      //Bin1 muTau
      data->SetBinContent(1,5.0);
      data->SetBinError(1,sqrt(5.0));

      //Bin2 eleTau
      data->SetBinContent(2,3.0);
      data->SetBinError(2,sqrt(3.0));

       //Bin3 SR1
      data->SetBinContent(3,1.0);
      data->SetBinError(3,sqrt(1.0));

        //Bin4 SR2
      data->SetBinContent(4,2.0);
      data->SetBinError(4,sqrt(2.0));


      //Bin1 muTau bkg from PAS
      bkg->SetBinContent(1,8.59);
      bkg->SetBinError(1,(4.83));

      //Bin2 eleTau bkg from PAS
      bkg->SetBinContent(2,3.52);
      bkg->SetBinError(2,(3.39));
      
       //Bin3 SR1 bkg from PAS
      bkg->SetBinContent(3,1.58);
      bkg->SetBinError(3,(0.65));

      //Bin4 SR2 bkg from PAS
      bkg->SetBinContent(4,7.07);
      bkg->SetBinError(4,(2.25));
 
   
      float r_step = 0.01;
      int steps = 500;
      TH1F *cls = new TH1F("cls", "cls",  steps, (0.5 *r_step), ((0.5+ steps) *r_step));
   
   for(int i = 1; i < (steps + 1); i++) {
     std::cout << "  r    : " << (i * r_step) << std::endl;
   signal->SetBinContent(1,0.767 * i * r_step);
   signal->SetBinContent(2,0.266 * i * r_step);   
   signal->SetBinContent(3,0.48 * i * r_step);  
   signal->SetBinContent(4,0.42 * i * r_step);
  
   signal->SetBinError(1,0.2 * signal->GetBinContent(1)); 
   signal->SetBinError(2,0.2 * signal->GetBinContent(2)); 
   signal->SetBinError(3,0.25 * signal->GetBinContent(3));
   signal->SetBinError(4,0.25 * signal->GetBinContent(4)); 
 
 	TLimitDataSource* mydatasource = new TLimitDataSource(signal,bkg,data);
	TConfidenceLevel* myconfidence = TLimit::ComputeLimit(mydatasource,50000);
	//	std::cout << "  CLs    : " << myconfidence->CLs()  << std::endl;
     cls->Fill((i * r_step), myconfidence->CLs());

 delete mydatasource;
    delete myconfidence;

 }
   CLs Expected +- 1 sigma

        std::cout << "  Expected CLs_b    : " << myconfidence->GetExpectedCLs_b(0)  << std::endl;
        std::cout << "  Expected+1 CLs_b   : " << myconfidence->GetExpectedCLs_b(1) << std::endl;
        std::cout << "  Expected-1 CLs_b    : " << myconfidence->GetExpectedCLs_b(-1)  << std::endl;


    Int_t last = cls->FindLastBinAbove(0.05);
    std::cout << last << " "
    << cls->GetBinLowEdge(last) << " "
    << cls->GetBinWidth(last) << " "
    << cls->GetBinCenter(last) << " "
    << cls->GetBinContent(last) << " " << std::endl;
   
 cls->Draw();
 gr1 = new TGraph(cls);
   gr1->SetLineColor(2);
 gr2 = new TGraph(CLs_b(0));
   gr2->SetLineColor(4);
 gr3 = new TGraph(CLs_b(1));
   gr3->SetLineColor(5);
 gr4 = new TGraph(CLs_b(-1));
   gr4->SetLineColor(3);
 
  mg->Add(gr1);
  mg->Add(gr2);
  mg->Add(gr3);
  mg->Add(gr4);
 
mg->Draw("AC");
}