A and B set off from A and B at the same speed at the same time and walk toward each other. The place where they meet for the first time is 4 kilometers away from A. After meeting, they continue to move forward and return immediately after reaching the starting point of the other party. , meet for the second time at a distance of 3 kilometers from point B, find the distance between the two places of encounter.
甲、乙二人以均匀的速度分别从A、B两地同时出发，相向而行，他们第一次相遇地点离A地4千米，相遇后二人继续前进，走到对方出发点后立即返回，在距B地3千米处第二次相遇，求两次相遇地点之间的距离．
<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<gadget id="calculator">12 - 3</gadget>
<output>9</output>

<gadget id="calculator">9 - 4 - 3</gadget>
<output>2</output>

<result>2</result>