There are some big trees on both sides of the road, 50 trees on each side, and the distance between every two trees is 7 meters. How many meters is this road?
公路两旁有一些大树，每边50棵，每两棵之间相隔7米．这条路长有多少米．
<gadget id="calculator">50 - 1</gadget>
<output>49</output>

<gadget id="calculator">49 * 7</gadget>
<output>343</output>

<result>343</result>