If □□□□-□□□=1993, what is the maximum sum of the minuend and the subtrahend?
如果□□□□-□□□=1993，那么被减数与减数的和最大是多少．
<gadget id="calculator">999 + 1_993</gadget>
<output>2_992</output>

<gadget id="calculator">2_992 + 999</gadget>
<output>3_991</output>

<result>3_991</result>