Xiao Ming and a carrier pigeon travel from A to B, which is 200 meters apart. Both Xiao Ming and the carrier pigeon move forward at a constant speed. When Xiao Ming walks halfway. The carrier pigeon has arrived at B and then the carrier pigeon returns to meet Xiao Ming. Run to the finish line after meeting Xiao Ming, when Xiao Ming walks half way. After arriving at the finish line, walk towards Xiao Ming...until Xiao Ming reaches the end point. Xiao Ming and a carrier pigeon travel from point A to point B, which is 200 meters away, and both move forward at a constant speed. The carrier pigeon has arrived at B, how many meters has the carrier pigeon run in total?
小明和一只信鸽从A地到相距200米的B地，小明和信鸽都以匀速前行，当小明走了一半时．信鸽己经到了B然后信鸽返回与小明相向而行．遇到小明以后再跑向终点，当小明走了一半时．到达终点以后再与小明相向而行…直到小明到达终点小明和一只信鸽从A地到相距200米的B地，小明和信鸽都以匀速前行．信鸽己经到了B地，信鸽一共跑了多少米．
<gadget id="calculator">200 * 2</gadget>
<output>400</output>

<result>400</result>