Question: 
Write a python function to count the number of prime numbers less than a given non-negative number.


Model's Code:
def count_Primes_nums(n):
    if n < 2:
        return 0
    primes = [True] * n
    primes[0] = primes[1] = False
    for i in range(2, int(n**0.5) + 1):
        if primes[i]:
            for j in range(i*i, n, i):
                primes[j] = False
    return sum(primes)



Sample Correct Code:
def count_Primes_nums(n):
    ctr = 0
    for num in range(n):
        if num <= 1:
            continue
        for i in range(2,num):
            if (num % i) == 0:
                break
        else:
            ctr += 1
    return ctr


Asserts:
assert count_Primes_nums(5) == 2
assert count_Primes_nums(10) == 4
assert count_Primes_nums(100) == 25


Tests:
Test 1 of 3: PASS
Test 2 of 3: PASS
Test 3 of 3: PASS

Test 256 of 974: 183/256 (71.484375%): success