class Solution:
    def maximumLength(self, nums: List[int]) -> int:
        cnt = Counter(nums)
        res = cnt[1] - (cnt[1] % 2 ^ 1)
        del cnt[1]
        for x in cnt:
            t = 0
            while cnt[x] > 1:
                x = x * x
                t += 2
            t += 1 if cnt[x] else -1
            res = max(res, t)
        return res