Three people, A, B, and C, go to complete the task of planting trees. Given the time when A plants one tree, B can plant two trees, and C can plant three trees. They first worked together for 5 days and completed (1/3) of all tasks, then C rested for 8 days, B rested for 3 days, and A did not rest, and finally completed the task together. Question: Counting from the start of tree planting, how many days did it take to complete the task?
甲、乙、丙三人去完成植树任务，已知甲植一棵树的时间，乙可以植两棵树，丙可以植三棵树．他们先一起工作了5天，完成全部任务的(1/3)，然后丙休息了8天，乙休息了3天，甲没休息，最后一起完成任务．问：从开始植树算起，共用了多少天才完成任务？
<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) / 5</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 + 2 + 3</gadget>
<output>6</output>

<gadget id="calculator">(1/15) / 6</gadget>
<output>1/90 = around 0.011111</output>

<gadget id="calculator">(1/90) * 8</gadget>
<output>4/45 = around 0.088889</output>

<gadget id="calculator">(1/90) * 2 * 5</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">(4/45) + (1/9)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/3) - (1/5)</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">(7/15) / (1/15)</gadget>
<output>7</output>

<gadget id="calculator">5 + 8 + 7</gadget>
<output>20</output>

<result>20</result>