void histMk_1D_DMass_uds() {

#include <iostream.h>
#include <fstream.h>

  gROOT->Reset();

  // Root macro to produce D mass plots
  //#######################################################
  // Change these values to meet your condition
  //#######################################################
 
  // Output histogram name
  TString outFileNameBase("histo_1D_DMass_uds");
  TString outHistoFileName(outFileNameBase+".root");
  TString outTxtFileName(outFileNameBase+".txt");

  // Info of input data/MC root files
  TString baseDir("/home1x/OtherMounts/hep03/khamano/R16b/Run3");
  TString nameBase("SP-998-BToDlnu-Run3-R16b");
  int nStart = 1;
  int nStop  = 282; //282

  // Name of the root tree in the input root files
  TString ntpName("ntp2");

  //###################################################################

  // Chain input root files.
  cout << "start chain\n";

  TChain * chainMC = new TChain(ntpName);
  for (Int_t i=nStart; i<=nStop; i++) {
  chainMC->Add(baseDir+"/"+nameBase+"-"+i+".root");
  }
  TTree * treeMC = chainMC;


  // Define histograms
  int nbin = 70;
  double xmin = 1.8;
  double xmax = 1.94;

  TH1D *Cont_D0 = new TH1D("Cont_D0","D mass (D0)",nbin, xmin,xmax);
  TH1D *Cont_Dch = new TH1D("Cont_Dch","D mass (Dch)",nbin, xmin,xmax);


  // Define cuts ####################
  // Cuts on D decay modes:
  TCut * cut_D0 = new TCut("DDecayMode==1"); //D0 -> Kpi
  TCut * cut_Dch = new TCut("DDecayMode==5"); //Dch -> Kpipi


  // Project trees
  treeMC->Project("Cont_D0","DMass",*cut_D0);
  treeMC->Project("Cont_Dch","DMass",*cut_Dch);


  // Open output file and write histograms in it. ######
  TFile *f = new TFile(outHistoFileName, "Recreate");

  Cont_D0->Write();
  Cont_Dch->Write();

  f->Write();
  f->Close();


  //#######################################################################
  // Open output txt file and save parameters. #####
  ofstream outFile(outTxtFileName); //open output file
  if (!outFile) {
    cout << "Cannot open file " << outFile << endl;
  }
  outFile.setf(ios::fixed);
  outFile.setf(ios::showpoint);
  outFile << "outFileNameBase = " << outFileNameBase << endl;
  outFile.close();

}