A community wants to plant trees on both sides of a 52-meter-long path, one tree every 4 meters, and no trees at both ends. How many saplings are needed in total?
某小区要在52米长的小路两边种树，每隔4米种一棵，两头都不种．一共需要准备多少棵树苗？
<gadget id="calculator">52 / 4</gadget>
<output>13</output>

<gadget id="calculator">13 - 1</gadget>
<output>12</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<result>24</result>