Not all restriction enzymes necessarily cleave DNA at rotationally symmetric sites. For example, the recognition site of the restriction enzyme Bst XI is 5' CCA^NTGG, where the symbol ^ represents the cleavage site and N means any nucleotide. Make the simplifying assumptions that equal amouts of all four nucleotides exist in the human genome, and that its base sequence is random. How frequently would you expect to find Bst XI recognition sites in the human genome