generators.ET0LTreeGrammar:
  (
    { leaf },
    { F1:5, F2:5 ,F3:5, leaf:0 },
    {
      { leaf -> F1[leaf, leaf, leaf, leaf, leaf],
        leaf -> F2[leaf, leaf, leaf, leaf, leaf],
        leaf -> F3[leaf, leaf, leaf, leaf, leaf] }
    },
    leaf
  )
