void pl_XY_trk(Int_t NSt=4, Double_t MinEff=0.5, Double_t dThr=0.01){
  //  TCanvas *can = new TCanvas("can22","can22");
  //  can->Divide(2,2); 
  TCanvas *can = new TCanvas("can","can",50,0,800,800);
  can->Divide(3,NSt); 

 gPad->SetFillColor(0);
 gStyle->SetPalette(1);
 gStyle->SetOptStat(kTRUE);
 gStyle->SetOptStat(11);

 gROOT->cd();
 gROOT->SetDirLevel(1);

 TH1 *h;
 TH1 *h1;
 TH2 *h2; 
 TH2 *h2m;
 TString hname="";

 // if (h!=NULL) h->Delete();
 Int_t iCan=1;
 Double_t eff[NSt];
 Double_t Nall;
 //if(NULL != h2)  h2->Delete();
 //if(NULL != h2m) h2m->Delete();

 for (Int_t iSt=0; iSt<NSt; iSt++) {
 can->cd(iCan++);
 gROOT->cd();
 hname=Form("hXY_AllStations_%d",iSt);
  h2=(TH2 *)gROOT->FindObjectAny(hname);
  if (h2!=NULL) {
      h2->Draw("colz");
      TH2D *h2acc=(TH2D *)h2->Clone(Form("Acc_%d",iSt));
      //h2acc->Divide(h2,h2,1.,1.,"B"); 
      h2acc->Reset();
      Int_t    Nbins=h2->GetNbinsX()*h2->GetNbinsY();
      Double_t dMax=dThr*h2->GetMaximum();
      for(Int_t i=0; i<Nbins; i++) 
	h2->GetBinContent(i+1) < dMax  ?  h2acc->SetBinContent(i+1,0.) : h2acc->SetBinContent(i+1,1.);  
      TH2D *h2aall=(TH2D *)h2->Clone(Form("ALL_acc%d",iSt));
      h2aall->Multiply(h2aall,h2acc,1.,1.,"B");
      Nall=h2aall->Integral();
      can->cd(iCan++);
      gROOT->cd();
      hname=Form("hXY_MissedStation_%d",iSt);
      h2m=(TH2 *)gROOT->FindObjectAny(hname);
      if (h2m!=NULL) {
      h2m->Draw("colz");
      Double_t Nmis=h2->GetEntries();
      Double_t NmisI=h2->Integral();
      TH2D *h2missed=(TH2D *)h2->Clone(Form("Missed_%d",iSt));
      h2missed->Multiply(h2m,h2acc,1.,1.,"B");
      Double_t NmisaI=h2missed->Integral();
      eff[iSt]=1. - NmisaI/(Nall+NmisaI);
      cout << "Efficiency of Station "<<iSt<<": all "<<Nall<<", mis "<<Nmis<<", "<<NmisI<<", "<<NmisaI
	   << " -> "<<Form("%6.3f",eff[iSt])<<endl;

      can->cd(iCan++);
      hname=Form("Efficiency_%d",iSt);
      TH2D *h2eff=(TH2D *)gROOT->FindObjectAny(hname);
      if(NULL != h2eff) h2eff->Delete();
      h2eff=(TH2D *)h2->Clone(hname);
      hname=Form("Total_%d",iSt);
      TH2D *h2tot=(TH2D *)gROOT->FindObjectAny(hname);
      if(NULL != h2tot) h2tot->Delete();
      h2tot=(TH2D *)h2m->Clone(hname);
      h2tot->Add(h2tot,h2,1.,1.);
      h2tot->Multiply(h2tot,h2acc,1.,1.,"B");
      h2eff->Reset();
      h2eff->Divide(h2,h2tot,1.,1.,"B");
      h2eff->SetTitle(Form("Efficiency of station %d",iSt));
      //h2frac->SetMaximum(0.99);
      h2eff->GetZaxis()->SetRangeUser(MinEff, 1.);
      h2eff->Draw("colz");
      gPad->Update();    
      h2eff->Draw("colz");

      if(1){
	TPad *newpad=new TPad("newpad","a transparent pad",0,0,1,1);
	newpad->SetFillStyle(4000);
	newpad->Draw();
	newpad->cd();
	TPaveLabel *tit = new TPaveLabel(0.2,0.75,0.45,0.9,Form(" <eff>: %5.3f",eff[iSt]));
	tit->SetFillColor(0);
	tit->SetTextFont(52);
	tit->SetBorderSize(1);
	tit->Draw();
      }
   }
 }else 
   {
     cout << hname << " not found" << endl;
   }
 }
 cout << "Eff-summary: Nall, effs = "<<Nall;
 for (Int_t iSt=0; iSt<NSt; iSt++) cout << Form(", %6.3f",eff[iSt]);
 cout <<endl; 

 can->SaveAs("pl_XY_trk.pdf");

}