Problem10570--ABC122 —— D - We Like AGC

10570: ABC122 —— D - We Like AGC

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Time Limit : 1.000 sec  Memory Limit : 512 MiB

Description

You are given an integer $N$. Find the number of strings of length $N$ that satisfy the following conditions, modulo $10^9+7$:

-   The string does not contain characters other than `A`, `C`, `G` and `T`.
-   The string does not contain `AGC` as a substring.

-   The condition above cannot be violated by swapping two adjacent characters once.


Notes
A substring of a string $T$ is a string obtained by removing zero or more characters from the beginning and the end of $T$.
For example, the substrings of `ATCODER` include `TCO`, `AT`, `CODER`, `ATCODER` and (the empty string), but not `AC`.

Input

Input is given from Standard Input in the following format:

```
$N$
```

Output

Print the number of strings of length $N$ that satisfy the following conditions, modulo $10^9+7$.

Constraints

-   $3 \leq N \leq 100$

Sample 1 Input

3

Sample 1 Output

61
There are $4^3=64$ strings of length 3 that do not contain characters other than A, C, G and T. Among them, only AGC, ACG and GAC violate the condition, so the answer is 64−3=61.

Sample 2 Input

4

Sample 2 Output

230

Sample 3 Input

100

Sample 3 Output

388130742

Source/Category