Consider the following cd:

Grammar ~ {Statement}.
Statement = NonTerminal "=" Expression ".".
Expression ~ Term {"|" Term}.
Term ~ Factor {Factor}.
Factor : NonTerminal | Terminal | Compound | Bracketed | Curlyed.
Compound = "(" Expression ")".
Bracketed = "[" Expression "]".
Curlyed = "{" Expression "}".
NonTerminal = Ident.
Terminal = String.

Unfortunately, this cd is not self-describing, but almost.
When you put the above cd in file g.cd and also into file g.input
and you use the following g.beh file:

Main {
{{
  public static void main(String args[]) throws Exception {
    Grammar g = Grammar.parse(System.in);
    System.out.println(" done ");
  }
}}
}

you will get syntax error messages when you run the program.

Your task is to find a small change to g.input that makes it
a legal input. The two changes are of the following form:

Replace all occurrences of UNKNOWN1 by UNKNOWN2.
Replace all occurrences of UNKNOWN3 by UNKNOWN4.

Find the UNKNOWNs.