Ana is playing the game "pick-up sticks."安娜正在玩“捡棍子”的游戏。
She drops some sticks on a table and then picks them all up following these rules:她把一些木棍放在桌子上，然后按照以下规则把它们全部捡起来：
- You may pick up one stick at a time;你可以一次捡一根棍子；
- You may pick up a stick only if it is on top: no other stick may be covering it.只有当某根木棍在最上面，即没有其他木棍压在它上面时，你才可以把它捡起来。
Example:例子:
3 sticks are dropped and look like this. Press play to see how Ana picks them up in order:三根棍子掉落下来，排列成这样。点击播放，看看安娜是如何依次捡起它们的：
Question:问题：
Ana dropped 6 sticks like this:安娜像这样扔下了 6 根木棍：
In which order should she pick them up?她应该按什么顺序去接他们？
Explanation 解释
Answer: 答案:
Explanation: 解释:
Explanation: 解释:The sticks above are arranged in order, from left to right, from top to bottom in the pile of sticks. Every time the top stick is removed, there is then only one stick that is not covered by another. The order the sticks are picked is shown below:上面的木棍按从左到右、从上到下的顺序排列成一堆。每次移除最上面的木棍时，就只剩一根木棍未被其他木棍遮盖。所选木棍的顺序如下：
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