A beekeeper inspects a straight row of n hives, left to right. Hive i holds h[i] units of honey. To avoid agitating neighbouring colonies, the keeper may not harvest two hives that sit directly next to each other in the row. Harvesting no hives at all is allowed (yielding 0).
Determine the maximum total honey the keeper can collect.
Input format
Line 1: the integer n.
Line 2: n space-separated non-negative integers h[0] h[1] ... h[n-1].
Output format
A single integer: the maximum total honey collectable with no two chosen hives adjacent.
Constraints
- 1 <= n <= 18
- 0 <= h[i] <= 1000