The sum of eight unequal positive integers is 88. Arrange these eight numbers from small to large, what is the largest fifth number?
八个互不相等的正整数之和是88，将这八个数从小到大排列，第5个数最大是多少．
<gadget id="calculator">1 + 2 + 3 + 4</gadget>
<output>10</output>

<gadget id="calculator">88 - 10</gadget>
<output>78</output>

<gadget id="calculator">78 - 1 - 2 - 3</gadget>
<output>72</output>

<gadget id="calculator">72 / 4</gadget>
<output>18</output>

<result>18</result>