How many even numbers are there among the natural numbers from 0 to 2003?
从0到2003的自然数中，偶数有多少个．
<gadget id="calculator">1 + 2_003</gadget>
<output>2_004</output>

<gadget id="calculator">2_004 / 2</gadget>
<output>1_002</output>

<result>1_002</result>