import sys
from collections import deque

input = sys.stdin.buffer.readline

N = int(input())
A = tuple(map(int, input().split()))
B = tuple(map(int, input().split()))
T = [[] for _ in range(N)]
for _ in range(N - 1):
    u, v = (int(x) - 1 for x in input().split())
    T[u].append(v)
    T[v].append(u)

d = deque([(0, -1)])
dp0 = list(A)
dp1 = [0] * N

dfs_order = []
while d:
    v, p = d.pop()
    for x in T[v]:
        if x == p: continue
        dfs_order.append((v, x))
        d.append((x, v))

for v, x in reversed(dfs_order):
    dp0[v] += max(dp0[x], dp1[x])
    dp1[v] += max(dp0[x], dp1[x] + B[v] + B[x])
print(max(dp0[0], dp1[0]))