The school organized students to plant trees along the west bank of Longxi Port on March 12th, planting one tree every 8 meters from north to south. If two people planted one tree together, a total of 312 people would be needed. How long is Longxi Port in meters?
学校组织学生于3月12日这天沿龙溪港西岸植树，从北到南每隔8米栽一棵，如果两人合栽一棵，共需312人，龙溪港长多少米？
<gadget id="calculator">312 / 2</gadget>
<output>156</output>

<gadget id="calculator">156 - 1</gadget>
<output>155</output>

<gadget id="calculator">8 * 155</gadget>
<output>1_240</output>

<result>1_240</result>