# O Running Time

Find the big-O running time of the following program that finds all lists with length equal to the length $$n$$ of an input list $$l$$ and elements only from the elements of the input list (the input list has no duplicate elements):

• It has a list of lists $$A$$ to return, which begins containing one empty list

• It repeats the following steps $$n$$ times

• For each list $$m$$ in $$A$$, it adds $$n$$ lists, the lists formed by adding each element of $$l$$ to $$m$$ (each of these will have one more element than $$m$$), to another list $$B$$

• It assigns the value $$B$$ to $$A$$

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