[프로그래머스/python] 소수 찾기

def solution(n):

    sieve = [True] * (n+1)
    m = int(n ** 0.5)
    
    for i in range(2, m + 1):
        if sieve[i] == True:           
            for j in range(i+i, n+1, i):
                sieve[j] = False

    return len([i for i in range(2, n+1) if sieve[i] == True])