After typing a manuscript, there are still 2400 characters after typing (2/5). How many characters are there in this manuscript?
打一份稿件，打了(2/5)后还有2400个字，这份稿件共有多少个字．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">2_400 / (3/5)</gadget>
<output>4_000</output>

<result>4_000</result>