Types: 
- N: int
- A: List[int]
- a: List[int]
- b: List[int]

Ranges: 
- 2 ≤ N ≤ 10^5
- 0 ≤ A[i] ≤ 10^9
- 1 ≤ a_i, b_i ≤ N

Addtl Info: 
- The given graph is a tree.
