CODE IN PYTHON

def perfect_match(rna): This function takes in an RNA string and returns the total possible number of perfect matchings of nucleotide bases. For a graph G, a matching is a collection of edges for which no node belongs to more than one edge in the collection. A matching on G is perfect if every node in the graph is matched; in other words, every nucleotide is paired (each U has a corresponding A and each C has a corresponding G) in a perfect match. Matching nucleotides is part of important RNA base pairing interactions such as RNA folding, a process in which the single-stranded RNA molecule twists around on itself. Figure 4. The bonding graph for the RNA string s = UAGCGUGAUCAC Figure 5. A perfect matching on the basepair edges is highlighted in red and represents a candidate secondary structure for the RNA strand. Example: Sample input RNA string: "CACUAGUGCGAU" * The returned total number of perfect matchings: 36