Suppose X and Y are two different numbers selected from 1-20, then what is the maximum value of (X+Y)/(XY)
设X和Y是选自1-20中的两个不同的数，那么(X+Y)/(X-Y)的最大值是多少
<gadget id="calculator">20 + 19</gadget>
<output>39</output>

<gadget id="calculator">20 - 19</gadget>
<output>1</output>

<gadget id="calculator">39 / 1</gadget>
<output>39</output>

<result>39</result>