To make the three-digit number "5__3" divisible by 3, what is the smallest number that can be filled in "__"
要使三位数"5__3"能被3整除，"__"里最小能填多少
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">9 - 8</gadget>
<output>1</output>

<result>1</result>