import string
import random


def generate_random_string(length):
    """
    Create a string of random characters of specified length
    """
    chars = [
        char for char in string.ascii_uppercase + string.digits + string.ascii_lowercase
        if char not in 'aAeEiIoOuU1l'
    ]
    return ''.join(random.choice(chars) for i in range(length))