A pile of pencils, counting 3 by 3, or counting 4 by 4 are exactly counted, what is the minimum number of pencils in this pile.
一堆铅笔，3枝3枝地数，或4枝4枝地数都正好数完，这堆铅笔至少多少枝．
<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<result>12</result>