2008+2007-2006-2005+2004+2003-2002-2001+2000+1999-1998-1997+...+4+3-2-1=how many.
2008+2007-2006-2005+2004+2003-2002-2001+2000+1999-1998-1997+…+4+3-2-1=多少．
<gadget id="calculator">2 * 1_004</gadget>
<output>2_008</output>

<result>2_008</result>