Description

Little SLM is preparing for an English exam and is memorizing vocabulary words like crazy. SLM decides to memorize words once a day, normally between 6:20-7:00 AM before getting up. He has a special skill: he can start memorizing words at 23:35 on day $i$ and continue until 00:25 on day $i+1$, which counts as memorizing words on both days. However, this skill cannot be used consecutively twice, as it would be too exhausting. For example: using the skill on days 1 and 2, then again on days 3 and 4 is not allowed. But using the skill on days 1 and 2, then normal memorization on day 3, and using the skill again on days 4 and 5 is allowed.
Little SLM wants to memorize words for $n$ days and wants to know how many valid ways there are to do this. Note that using the skill between day $n$ and day $n+1$ or between day $0$ and day $1$ is not allowed.

Input Format

A single line containing a positive integer $n$ ($n \leq 80$).

Output Format

A single integer representing the number of valid memorization plans.

Sample

5

6