N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
edge = [[] for _ in range(N)]
for i in range(N-1):
  a,b = map(int, input().split())
  edge[a-1].append(b-1)
  edge[b-1].append(a-1)
import sys
sys.setrecursionlimit(10**6)

def dfs(v, p):
  if p>=0 and len(edge[v])==1:
    offs, ons = max(A[v],0), max(A[v],B[v]+B[p])
    return offs, ons 
  offs, ons = A[v],0
  for u in edge[v]:
    if u!=p:
      off, on = dfs(u, v)
      offs += off
      ons += on
  if p==-1:
    return offs, ons
  return max(offs,ons),max(offs,ons+B[v]+B[p])

off, on = dfs(0, -1)
print(max(off,on))