Count number of strings of length N with following properties:
A. Consists of char ‘A’ and ‘B’ only.
B. There is atleast one occurrence of 3 consecutive Bs.
Input: Only line having integer N.
Output: Number of string with given properties. As then number can be very large print it with modulo 10^9+7.
Sample Input 1:
3
Sample Input 2:
1
Explanation: Only possible string “BBB”
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