n = int(input())
a = list(map(int, input().split()))
b = list(map(int, input().split()))

g = [[] for _ in range(n)]
for _ in range(n - 1):
  u, v = map(int, input().split())
  u -= 1
  v -= 1
  g[u].append(v)
  g[v].append(u)

dp = [[0 for _ in range(2)] for _ in range(n)]
src = 0
st = [~ src, src]
par = [None for _ in range(n)]
while len(st) > 0:
  cur = st.pop()
  if cur >= 0:
    for nxt in g[cur]:
      if nxt == par[cur]:
        continue
      par[nxt] = cur
      st.append(~ nxt)
      st.append(nxt)
  else:
    dp[~ cur][0] += a[~ cur]
    if not par[~ cur] is None:
      dp[par[~ cur]][0] += max(dp[~ cur])
      dp[par[~ cur]][1] += max(dp[~ cur][0], dp[~ cur][1] + b[~ cur] + b[par[~ cur]])

print(max(dp[src]))