Among the national uniform shoe sizes, there are 14 sizes for adult men's shoes, the smallest size is 23.5 cm, and the difference between two adjacent sizes is 0.5 cm. What is the largest size?
全国统一鞋号中，成年男鞋有14种尺码，其中最小的尺码是23.5厘米，各相邻两个尺码都相差0.5厘米，其中最大的尺码是多少？
<gadget id="calculator">14 - 1</gadget>
<output>13</output>

<gadget id="calculator">13 * 0.5</gadget>
<output>6.5</output>

<gadget id="calculator">23.5 + 6.5</gadget>
<output>30</output>

<result>30</result>