def calculate_total_items(input_text):
    """
    Calculates the total number of items in a sentence.

    This function takes a string where the speaker states the number of each item they have.
    It then calculates the total number of items.

    Args:
    input_text (str): A string where the speaker states the number of each item they have.

    Returns:
    int: The total number of items.
    """
    items = input_text.split(", ")
    total_items = 0

    for item in items:
        if "two" in item:
            total_items += 2
        elif "three" in item:
            total_items += 3
        elif "four" in item:
            total_items += 4
        elif "a" in item:
            total_items += 1

    return total_items

