题目描述
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,GandT. - The string does not contain
AGCas a substring. - The condition above cannot be violated by swapping two adjacent characters once.
Constraints
- $3 \leq N \leq 100$
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.
Examples
Input
3
Output
61
Input
4
Output
230
Input
100
Output
388130742
输入格式
见题面
输出格式
见题面
样例输入
4
样例输出
230