You are given six characters G I T H U B to make a string of length $N$. However there are some limitations:

• I can not come directly after G.
• H can not come directly after G or B.
• T can not come directly after T or U.
• The string should be a palindrome.

How many ways are there to form a string of length $N = 7162534$?

Submit the answer modulo $1000000007$.