18. (10 points) Based on the following grammar, draw an annotated parse tree that shows how the syntax tree for a-(b c) is constructed. mknode() is a function that creates a node for a syntax tree. A good way to do this is to first draw the parse tree, then annotate the leaves and propogate the annotations3up the tree. After you're done, E.n of the root of the parse tree will be the abstract syntax tree. Your parse tree will look something like the following:You can see that this particular node