It takes 12 days for A and B to process a batch of parts together. Now A will do it alone for 8 days, and then B will replace A and do it alone for 14 days, which is just completed. How many days does it take for A to process this batch of parts alone?
甲、乙两人共同加工一批零件需12天完成，现由甲先单独做8天后，再由乙接替甲单独做14天，刚好完成．甲单独加工这批零件需多少天完成？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">(1/12) - (1/18)</gadget>
<output>1/36 = around 0.027778</output>

<gadget id="calculator">1 / (1/36)</gadget>
<output>36</output>

<result>36</result>