Complete the semantic rules below $($on the right$)$ that specify how the val attribute is computed, that represents the decimal value of a Roman numeral. Note that c$=100,$ l$=50,$ x$=10,$ v$=5,$ i$=1,$ and symbol values are added except: i before v or x indicates one less $($e$.$g$.,$ iv is $4)$ and x before l or c indicates ten less $($e$.$g$.,$ xc is $90).$ Use the semantic rules to evaluate the Roman numeral xciv, showing clearly all the calculation steps. $(3$ marks$)$