Table: list of whose line is it anyway? uk episodes
Question: How many unique performers were featured in the UK episodes of "Whose Line is it Anyway?"
Step 1 (Operation, Indexing): performer 1, performer 2, performer 3, performer 4
Step 2 (Reasoning, Analytic entailment): unique, only count different performers
Step 3 (Operation, Grouping): name of the performer
Step 4 (Reasoning, Aggregating): COUNT, different names of the performer
Answer: 19