The sum of the numerator and the denominator is 2013. How many real fractions are there?
分子与分母的和是2013的最简真分数有多少个．
<gadget id="calculator">1_006 - 335 - 91 - 16</gadget>
<output>564</output>

<gadget id="calculator">564 + 30 + 5 + 1</gadget>
<output>600</output>

<result>600</result>