class Solution:
    def minNumberDisappeared(self , nums: List[int]) -> int:
        # write code here
        nums.sort()
        if 1 not in nums:
            return 1
        i = nums.index(1) # 查找1在哪个地方,因为是正整数,后面直接从1开始
        s = 1
        for  v in nums[i:]:
            if v == s: # 遍历里面的内容,依次判断缺失,要是依次加一不等里面的值
                s = s + 1 # 就返回值
            else:
                break
        return s