if(Ev_end==0){ 
     if (Ev_start==0){
        Ev_end=Int_t((fRootManager->GetInChain())->GetEntries());
	 }else {
       Ev_end =  Ev_start;  
       if ( Ev_end > ((fRootManager->GetInChain())->GetEntries()) ){
           Ev_end = (Int_t) (fRootManager->GetInChain())->GetEntries();
       }
       Ev_start=0;
     }
  }else{
	  Int_t fileEnd=(fRootManager->GetInChain())->GetEntries();
	  if(Ev_end > fileEnd){
		  cout << "-------------------Warning---------------------------" << endl;
		  cout << " -W CbmRunAna : File has less events than requested!!" << endl;
		  cout << " File contains : " << fileEnd  << " Events" << endl;
		  cout << " Requested number of events = " <<  Ev_end <<  " Events"<< endl;
		  cout << " The number of events is set to " << fileEnd << " Events"<< endl;
		  cout << "-----------------------------------------------------" << endl;
	      Ev_end = fileEnd;
	  }
	  
  }