A six-digit number is composed of several numbers 1, 2, and 3 and is a multiple of 6. How many such six-digit numbers are there?
由若干个数字1、2、3组成一个六位数，且为6的倍数，一共有多少个这样的六位数？
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<gadget id="calculator">5 + 1 + 20 + 30 + 5</gadget>
<output>61</output>

<result>61</result>