8. A staircase has a total of 12 steps. When a person climbs the stairs, they sometimes take one step at a time, and sometimes two steps at a time. The number of ways this person can climb the stairs is $\qquad$.
8. 233 Detailed Explanation: Let the action of taking two steps at once be denoted as $a$. Since the staircase has a total of 12 steps, the action $a$ can be performed at most 6 times; let the action of taking one step at a time be denoted as $b$. Therefore, the entire process of going upstairs consists of $k$ actions of $a$ and $12-2k$ actions of $b$, where $k$ can take the values $0,1,2,3,4,5,6$. For a certain $k$, the number of all permutations is $\frac{[k+(12-2k)]!}{k!\cdot(12-2k)!}=\frac{(12-k)!}{k!(12-2k)!}$. Therefore, the total number of ways to go upstairs is $\sum_{k=0}^{6} \frac{(12-k)!}{k!(12-2k)!}=233$.