Problem: Consider an array of integers, where every element is from to , and every integer from to appears at least once.
Let the array be constructed as follows: for the -th element of , is the distance to the closest element in which is not equal to . In other words, .
For example, if , then .
Calculate the number of different arrays you can obtain if you consider all possible arrays , and print it modulo .
Input Format: The only line of the input contains two integers and (; ).
Output Format: Print one integer — the number of different arrays you can obtain, taken modulo .