Person A and Person B start from point A at the same time and travel back and forth between points A and B at a constant speed. When A walked 5 full lengths, B walked exactly 10 full lengths. May I ask how many times did A and B meet in total during their journey? (Meeting head-on and catching up are considered encounters)
甲乙两人同时从A地出发，在AB两地之间匀速折返行进．当甲行走了5个全长的时候，乙恰好行走了10个全长．请问在甲乙两人行进的过程中，一共相遇了多少次？(迎面碰到和追上都算相遇)
<result>20</result>