fig = pyplot.gcf()
    fig.set_size_inches(20, 15)
    ax1 = fig.add_subplot(211)

    ax1.set_ylabel('L_m')
    ax1.set_xlabel('Values of Lambda')

    pyplot.plot(alpha, result)
    pyplot.show()


if __name__ == "__main__":
    # read all required files
    from FileReader import FileReader
    file = FileReader()
    vocab, unigram, bigram = file.readAll()

    # compute the probability of each word
    from LanguageModel import LanguageModel
    lm = LanguageModel()
    P_w = lm.Unigram(unigram)
    vocab_size = len(vocab)
    P_w1_w2, words = lm.Bigram(bigram, vocab_size)

    sentence = 'The sixteen officials sold fire insurance'
    word_list = sentence.upper().split()

    # calculate log-likelihood under unigram
    result_unigram = log_likelihood_unigram(word_list, P_w, vocab)
    print("Log-likelihood under unigram model is " +
          str(math.log(result_unigram)))