class Solution:
    def longestConsecutive(self, nums: List[int]) -> int:
        n = len(nums)
        if n < 2:
            return n
        nums.sort()
        ans = t = 1
        for a, b in pairwise(nums):
            if a == b:
                continue
            if a + 1 == b:
                t += 1
                ans = max(ans, t)
            else:
                t = 1
        return ans