Consider the following syntax directed definition of any desk calculator:
- $L \rightarrow En \{ \text{print}(E.val) \}$
- $E \rightarrow E1 + 1 \{ E.val = E1.val + Z.val \}$
- $E \rightarrow Z E \cdot val = Z \cdot val$
- $Z \rightarrow Z1 ^* F \{ Z.val = Z1.val ^* F.val \}$
- $Z \rightarrow F \{ Z \cdot val = F \cdot val \}$
- $F \rightarrow ( E ) \{ F \cdot val = E \cdot val \}$
- $F\rightarrow digit \{ F \cdot val = digit \cdot lexval \}$
How many internal nodes are there in annotated parse tree for input $7 ^* 4 + 2n$?
- $9$
- $6$
- $10$
- $11$