#include<vector>
#include<iostream>

#include"TFile.h"
#include"TTree.h"
#include"TRoot.h"

using namespace std;

int main(){
  gROOT->ProcessLine("#include <vector>"); 
  TFile f("AnalysisSkeleton.aan.root");
  TTree* t;
  f.GetObject("CollectionTree",t);

  unsigned int n_jets;
  vector<double>* eta;

  t->SetBranchAddress("NJets",&n_jets);
  t->SetBranchAddress("JetsEta",&eta);

  int n=0;

  for (int i = 0; i!=t->GetEntries(); i++)
    {
      t->GetEntry(i+1);
      n+=n_jets;
    }
  cout<<n<<endl;
  delete t;
  f.Close();
  return 0;
}