import sys
from collections import deque

N = int(input())
a = list(map(int,input().split()))
b = list(map(int,input().split()))
edge = [[] for i in range(N)]
for _ in range(N-1):
    u,v = map(int,input().split())
    edge[u-1].append(v-1)
    edge[v-1].append(u-1)

deq = deque([0])
parent = [-1] * N
res = []
while deq:
    v = deq.popleft()
    res.append(v)
    for nv in edge[v]:
        if nv!=parent[v]:
            parent[nv] = v
            deq.append(nv)

res = res[::-1]

exist_dp = [0] * N
not_exist_dp = [0] * N

for v in res:
    #not_exist_dp
    not_exist_dp[v] = a[v]
    for nv in edge[v]:
        if nv!=parent[v]:
            not_exist_dp[v] += max(exist_dp[nv],not_exist_dp[nv])

    #exist_dp
    for nv in edge[v]:
        if nv!=parent[v]:
            exist_dp[v] += max(b[v]+b[nv]+exist_dp[nv],not_exist_dp[nv])

print(max(exist_dp[0],not_exist_dp[0]))