When a number is divided by 4, the remainder is 1, when divided by 6, the remainder is 3, and when divided by 8, the remainder is 5. What is the smallest natural number that satisfies the condition?
一个数除以4余1，除以6余3，除以8余5，那么满足条件的最小自然数是多少．
<gadget id="calculator">2 * 2 * 2 * 3</gadget>
<output>24</output>

<gadget id="calculator">24 - 3</gadget>
<output>21</output>

<result>21</result>