There is a road with a length of 200 meters, and a tree is planted every 4 meters on both sides of the road (neither end is planted), how many trees are planted in total?
有一条长200米的路，在路的两边每隔4米植树一棵(两头都不种)，一共植树多少棵？
<gadget id="calculator">200 / 4</gadget>
<output>50</output>

<gadget id="calculator">50 - 1</gadget>
<output>49</output>

<gadget id="calculator">49 * 2</gadget>
<output>98</output>

<result>98</result>