The manual group made 150 lanterns and sent 93 to the kindergarten. The remaining lanterns were packed in a box of three. How many boxes can be packed in total?
手工组做了150个灯笼，送给幼儿园93只，剩下的灯笼每3只装一盒，一共可以装多少盒？
<gadget id="calculator">150 - 93</gadget>
<output>57</output>

<gadget id="calculator">57 / 3</gadget>
<output>19</output>

<result>19</result>