Q43

Consider the following grammar: stmt $\rightarrow$ if expr then expr else expr; stmt | $Ò$ expr $\rightarrow$ term relop term | term term $\rightarrow$ id | number id $\rightarrow$ a | b | c number $\rightarrow [0-9]$ where relop is a relational operator $($e.g., $< , >,\ldots),$ $Ò$ refers to the empty statement, and if, then, else are terminals. Consider a program $P$ following the above grammar containing ten if terminals. The number of control flow paths in $P$ is________ . For example. the program if $e_1$ then $e_2$ else $e_3$ has $2$ control flow paths. $e_1 \rightarrow e_2$ and $e_1 \rightarrow e_3$.