A three-digit number 5□□ can be divisible by 3 and 5 at the same time. What is the maximum sum of the numbers in two □?
一个三位数5□□，能同时被3、5整除，两个□中的数的和最大是多少．
<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<result>13</result>