There are 336 red and yellow flags on the border of a hexagonal square. There are red flags inserted at each vertex of the hexagon, the same number of red flags on each side, and the same number of yellow flags inserted between every two red flags. It is known that there are 12 more yellow flags on each side than double the red flags, so how many common flags are inserted between every two red flags?
一个六边形广场的边界上插有336面红旗和黄旗．六边形的每个顶点处都插有红旗，每条边上的红旗数目一样多，并且每两面红旗间插有相同数目的黄旗．已知每条边上黄旗比红旗的2倍还多12面，那么每两面红旗间插有几面共旗？
<gadget id="calculator">6 * 12</gadget>
<output>72</output>

<gadget id="calculator">336 - 72</gadget>
<output>264</output>

<gadget id="calculator">6 + 264</gadget>
<output>270</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">6 + 12</gadget>
<output>18</output>

<gadget id="calculator">270 / 18</gadget>
<output>15</output>

<gadget id="calculator">2 * 15</gadget>
<output>30</output>

<gadget id="calculator">30 + 12</gadget>
<output>42</output>

<gadget id="calculator">15 - 1</gadget>
<output>14</output>

<gadget id="calculator">42 / 14</gadget>
<output>3</output>

<result>3</result>