The sum of the two numbers A and B is 1986. What is the maximum sum of the first and last digits of the product of these two numbers?
甲乙两个数的和是1986，这两个数的积的首末数字之和最大是多少．
<gadget id="calculator">9 + 9</gadget>
<output>18</output>

<result>18</result>