How can I Get only the value 9 from this input using xpath?

I have some HTML as shown below

<ol Class="z1">
        <li><h3>Number Theory - HCF LCM</h3>
            <p lang="title">How many pairs of integers (x, y) exist such that the product of x, y and HCF (x, y) = 1080?</p>
            <ol class="xyz">
                <li>8</li>
                <li>7</li>
                <li>9</li>
                <li>12</li>
            </ol>
        <ul class="exp"><li class="grey fleft"><span class="qlabs_tooltip_bottom qlabs_tooltip_style_33" style="cursor:pointer;"><span><strong>Correct Answer</strong>Choice (C).</br>9</span> Correct answer</span></li><li class="primary fleft"><a href="hcf-lcm_1.shtml">Explanatory Answer</a></li><li class="grey1 fleft">HCF LCM</li><li class="red1 flrt">Hard</li>
        </ul>
        </li>
</ol>

I am interested in grabbing the value 9 under Correct Answer from the ul whose class is exp that follows the br

I wrote an existing Xpath query that gets everything but doesnt quite do the job "'.//ul[@class="exp"]/li/span/span/text()'"

Any help is highly appreciated?

Trying to run this xpath expression on scrapy

class BrickSetSpider(scrapy.Spider):
    name = "cat_spider"
    start_urls = ['http://iim-cat-questions-answers.2iim.com/quant/number-system/hcf-lcm/']

    def parse(self, response):
        CLASS_SELECTOR = '//ol[@class="z1"]/li'
        problems = []
        for lis in response.xpath(CLASS_SELECTOR):
            question = lis.xpath('.//p[@lang="title"]/text()').extract_first().strip()
            choices = lis.xpath('.//ol[@class="xyz"]/li/text()').extract()
            ANSWER_SELECTOR = './/ul[@class="exp"]/li/span/span/text()[not(contains(.,"Choice"))]'
            correct_answer = lis.xpath(ANSWER_SELECTOR).extract_first()
            explanation = lis.xpath('.//ul[@class="exp"]/li[2]/a/@href').extract_first().strip()
            difficulty = lis.xpath('.//ul[@class="exp"]/li[last()]/text()').extract_first().strip()
            p = Problem(question,choices, correct_answer, explanation, difficulty)
            print(question, choices, correct_answer)