function [subDirsNames] = GetSubDirsFirstLevelOnly(parentDir)
   % Get a list of all files and folders in this folder.
   files    = dir(parentDir);
   names    = {files.name};
   % Get a logical vector that tells which is a directory.
   dirFlags = [files.isdir] & strcmp(names, '.')==0 & strcmp(names, '..')==0;
   % Extract only those that are directories.
   subDirsNames = names(dirFlags);
end