Need help with Part $2$ and please draw the DFA.

Consider scanning literals for representing carbohydrates in chemistry. Such literals consist of one or more parts, each consisting of C$,$ H$,$ or O$,$ optionally followed by a decimal integer greater than $1($it can greater than $9).$ You may use D$0$ to mean decimal digits $0-9,$ D$1$ to

mean $1-9,$ and D$2$ to mean $29.($This is a computer science question, not a chemistry question. In particular, this specification allows bogus chemical formulas such as H$42.)$

a$.$ Give a regular expression for these carbohydrate literals. You may use the iteration

operators $*$ and $+$ and $?.$ ANSWER: $(($C$|$H$|0)($D$2*|$ D$1$D$0*|$ DO$*))+$

b$.$ Give a DFA that recognizes exactly these literals $($no $$ edges$).$ Don$$t forget to mark the

start state and all accepting states.

Make sure that you don$$t accept the empty string!