A local television station sends out questionnaires to determine if viewers would rather see a documentary, an interview show, or reruns of a game show. There were 300 responses with the following results: 90 were interested in a interview and documentary, but not reruns
12 were interested in an interview show and reruns, but not a documentary
42 were interested in reruns but not an interview show
72 were interested in an interview show but not a documentary
30 were interested in a documentary and reruns
18 were interested in an interview show and reruns
24 were interested in none of the three

Required:
How many are interested in exactly one kind of show?