There are two terminals A and B on both sides of the calm landscape lake. Two cruise ships, A and B, set off from A and B at the same time. They met for the first time at a distance of 700 meters from point A, and then the two ships continued to sail, and immediately turned back after reaching the opposite bank.
平静的景观湖两岸有A、B两个码头．甲乙两只游船船从A、B两地同时相向出发．在距A地700米处第一次相遇，随后两船继续航行，到达对岸后立即返航，在返航途中，两船距乙地400米处，第二次相遇，则AB两地距离多少米．
<gadget id="calculator">700 * 3</gadget>
<output>2_100</output>

<gadget id="calculator">2_100 - 400</gadget>
<output>1_700</output>

<result>1_700</result>