For construct a regular expression defining each of the following languages over the alphabet = {a

For construct a regular expression defining each of the following languages over the alphabet Σ = {a b} :

(i) All strings in which any h's that occur are found in clumps of an odd number at a time, such as abaabbbab.
(ii) All strings that have an even number of a's and an odd number of h's.
(iii) All strings that have an odd number of a's and an odd number of h's.