def primes_till_N(N:int):
    """ Generate all primes less than N

    Args:
        N (int): upper bound

    Returns:
        list: list of prime numbers
    """

    nums = [True] * N
    primes = []
    for x in range(2,N):
        if nums[x]:
            primes.append(x)
            for i in range(x, len(nums), x):
                nums[i] = False
    return primes