void load_hst(TString cstr="hst/default.hst.root"){
 // Read histogramms from the file
  TFile *fHist = TFile::Open(cstr,"READ");
 TIter next(fHist->GetListOfKeys());

 gROOT->cd();
 gDirectory->pwd();

  TObject* obj;
  TKey* key;
  TClass* cls;
  while( (key= (TKey*)next()) ){
    cls = TClass::GetClass(key->GetClassName());
    if(cls->InheritsFrom(TH1::Class()))
    {
      obj = fHist->Get(key->GetName());
      dynamic_cast<TH1*>(obj)->SetDirectory(gROOT);
    }
    else if(cls->InheritsFrom(TEfficiency::Class()))
    {
      obj = fHist->Get(key->GetName());
      dynamic_cast<TEfficiency*>(obj)->SetDirectory(gROOT);
    }
  }

  fHist->Close();
}