1997+1996-1995-1994+1993+1992...-2+1=how much.
1997+1996-1995-1994+1993+1992…-2+1=多少．
<gadget id="calculator">1_996 - 1_995 - 1_994</gadget>
<output>-1_993</output>

<gadget id="calculator">1_997 + (-1_993)</gadget>
<output>4</output>

<gadget id="calculator">1_996 / 4</gadget>
<output>499</output>

<gadget id="calculator">4 * 499</gadget>
<output>1_996</output>

<gadget id="calculator">1_996 + 1</gadget>
<output>1_997</output>

<result>1_997</result>