Suppose there is a pair of newborn bunnies in the pasture in the first month, each pair of male and female bunnies grew into a large male and female rabbits after two months later. After three months from the start, each pair of male and female rabbit can give birth to a pair of small bunnies every month. If the rabbits can live forever, how many pair of rabbits in the pasture in the first N month?
(1<=N<=90)(Very IMPORTANT)
Input
3
Output
2
Input
5
Output
5
Input
88
Output
1100087778366101931