20 times a number minus 1 can be divisible by 153. What is the smallest natural number?
一个数的20倍减去1能被153整除，这样的自然数中最小的是多少．
<gadget id="calculator">153 * 3</gadget>
<output>459</output>

<gadget id="calculator">459 + 1</gadget>
<output>460</output>

<gadget id="calculator">460 / 20</gadget>
<output>23</output>

<result>23</result>