Choose 3 numbers randomly from 1, 3, 5, 7 to form a three-digit number without repeating numbers. How many of these three-digit numbers are divisible by 3?
从1，3，5，7中任取3个数字组成没有重复数字的三位数，这些三位数中能被3整除的有多少个．
<gadget id="calculator">3 * 2 * 1 * 2</gadget>
<output>12</output>

<result>12</result>