A plans to use several working days to complete a certain task. From the third working day, B joins the work, and A and B have the same work efficiency. As a result, the task is completed 3 days ahead of schedule, then A plans to complete the work. how many days
甲计划用若干个工作日完成某项工作，从第三个工作日起，乙加入此项工作，且甲、乙两人工效相同，结果提前3天完成任务，则甲计划完成此项工作的天数是多少
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 - 2</gadget>
<output>2</output>

<gadget id="calculator">6 + 2</gadget>
<output>8</output>

<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">8 / 1</gadget>
<output>8</output>

<result>8</result>