Divide 400 into the sum of 20 prime numbers, and at the same time make the largest prime number as small as possible and the smallest prime number as large as possible, what is the difference between the largest and smallest prime numbers?
把400分成20个质数的和，同时使最大的质数尽可能小，最小的质数尽可能大，最大最小两质数的差是多少？
<gadget id="calculator">23 - 19</gadget>
<output>4</output>

<result>4</result>