import sys
input = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 7)
inf = 10**18

N = int(input())
A = tuple(map(int, input().split()))
B = tuple(map(int, input().split()))
G = [[] for _ in range(N)]
for _ in range(N - 1):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    G[a].append(b)
    G[b].append(a)

topo = []
par = [-1]*N
que = [0]
while que:
    s = que.pop()
    topo.append(s)
    for t in G[s]:
        if t == par[s]:
            continue
        par[t] = s
        G[t].remove(s)
        que.append(t)

dp_stay = [-inf] * N
dp_remove = [-inf] * N
for s in topo[::-1]:
    dp_remove[s] = A[s] + sum(max(dp_stay[c], dp_remove[c]) for c in G[s])
    dp_stay[s] = sum(max(dp_stay[c] + B[s] + B[c], dp_remove[c]) for c in G[s])

print(max(dp_stay[0], dp_remove[0]))