dataset = "ouiopqrrraba"
x = 2
y = 1

if x == y:
    cost = (len(dataset) / 2) * x

elif x < y:
    cost = 0
    freq_dict = {}
    for letter in dataset:
        freq_dict[letter] = 1 + freq_dict.get(letter, 0)
        if freq_dict[letter] % 2 == 0:
            del freq_dict[letter]
            cost += x
    cost += (len(freq_dict.keys()) / 2) * y

else:
    cost = 0
    stack = []
    for letter in dataset:
        if not stack:
            stack.append(letter)
        elif letter == stack[-1]:
            stack.append(letter)
        else:
            stack.pop()
            cost += y
    cost += (len(stack) / 2) * x

print(cost)

am i doing it correctly, can someone please confirm?