<E> ::= <E> + <T> | <T> <T> ::= <T> * <F> | <F> <F> ::= num | ( <E> )give parse trees for each of the following strings, where num is a token whose lexemes are decimal numerals.
<S> ::= <S> a <S> | a
Operators that are listed together have the same precedence, and the lines are in order of increasing precedence. All operators associate to the left. For example, a/b/c is understood to mean (a/b)/c, not a/(b/c).
Make your grammar unambiguous, so that it enforces the correct precedence and associativity rules.