A literal $($i$.$e$.,$ a leaf in the parse tree$)$ is said to have positive phase if it appears under an even number of negation symbols, and has negative phase if it appears under an odd number of negation symbols. $($For example, in the formula, not$(av$ not$(b^n$otc$)),$a and $c$ have negative phase, and $b$ has positive phase$).$ Give semantic actions to compute the phase of each literal in a formula.

$SF$

$F{F}^F$

$FFvF$

$F$notF

$F(F)$

$Fid$

$F$ true

$F$ false