There are 72 red flowers, 8 fewer yellow flowers than red flowers, and 7 fewer purple flowers than yellow flowers. How many purple flowers are there?
红花有72朵，黄花比红花少8朵，紫花比黄花少7朵，紫花有多少朵？
<gadget id="calculator">72 - 8 - 7</gadget>
<output>57</output>

<result>57</result>