Gardeners are planting trees beside a road. Plant 12 pine trees, plant three times as many willows as pine trees, and plant twice as many plane trees as willows. How many sycamore trees are planted?
园林工人在一条公路旁栽树木．栽松树12棵，栽的柳树是松树的3倍，栽的梧桐树是柳树的2倍．栽的梧桐树有多少棵？
<gadget id="calculator">12 * 3 * 2</gadget>
<output>72</output>

<result>72</result>