274. H-Index

class Solution:
    def hIndex(self, citations: List[int]) -> int:
        # max of x such that x is atleast n with x citation
        citations.sort(reverse=True)
        h=0
        for i in range(0,len(citations)):
            if citations[i]>=i+1:
                h=i+1
            else:
                break
        return h