int checkOAAnalTree(){

  


  TTree *tree = (TTree*)gFile->Get("TruthDir/Trajectories");
  if(!tree){
    std::cout << "Didn't find tree in oaAnalysis ... exit" << std::endl;
    return 1;
  }

  if(tree->GetEntries() != 10){    
    std::cout << "Wrong number of entries in oaAnalysis tree ! = " 
              << tree->GetEntries() << std::endl;
    return 1;
  }
  return 0;

}