def notPrime(self, n):
    l=[]
    for i in range(2,n):
        for j in range(2,n):
            if i*j not in l:
                l.append(i*j)
    return sorted(l)

class Solution:
    def countPrimes(self, n: int) -> int:
        non_prime = self.notPrime(n)
        prime = []
        for i in range(2,n):
            if i not in non_prime:
                prime.append(i)
        return(len(prime))