import re


def preprocess_text(text):
    """ Function for basic cleaning and pre-processing of input text

    Args:
        text (string): raw input text

    Returns:
        string: cleaned text
    """
    text = text.lower()
    text = re.sub(r"'s\b", "", text)
    text = re.sub("[^a-zA-Z]", " ", text)
    text = ' '.join([word for word in text.split() if len(word) >= 3]).strip()

    return text