def compose_tweet(days, vacation):
    """
    Composes the tweet that will be sent to the API.

    :param days: Number of days until the next vacation.
    :type days: int
    :param vacation: String that connects the tweet's sentence. Either "meio de ano" or "fim de ano".
    :type vacation: str
    """
    
    if days <= 0 or vacation == 'holiday':
        return "Boas férias!"
    elif days == 1:
        return "Falta 1 dia até as férias de " + vacation + " do ITA!"
    else:
        return "Faltam " + str(days) + " dias até as férias de " + vacation + " do ITA!"