parts = ["A", "B", "A", "C", "A", "B"]
limit = 2
answer = []
count = 0

parts.sort()
for i in range(len(parts)-1):
    if parts[i] == parts[i+1]:
        count += 1
        if count >= limit:
            answer.append(parts[i])
    else:
        count = 0

print(answer)