def ReverseComplement(Pattern):
    Pattern = Reverse(Pattern)
    Pattern = Complement(Pattern)
    return Pattern


def Reverse(Pattern):
    reversed = Pattern[::-1]
    return reversed


def Complement(Pattern):
    compl = ""
    complement_letters = {"A": "T", "T": "A", "C": "G", "G": "C"}
    for char in Pattern:
        compl += complement_letters[char]
    return compl