int make_mem_ntuple(const char* InputFile = 0, const char* NtupleFile = 0) {

  char  *input_file, *ntuple_file;

  if (InputFile) input_file = InputFile;
  else           input_file = gSystem->Getenv("MEM_INPUT_FILE");

  if (NtupleFile) ntuple_file = NtupleFile;
  else            ntuple_file = gSystem->Getenv("MEM_NTUPLE_FILE");

  mon->CreateMemUseNtuple(input_file,ntuple_file);
}