import sys;input=sys.stdin.readline
N, = map(int, input().split())
A = [0]+list(map(int, input().split()))
B = [0]+list(map(int, input().split()))

G = [set() for _ in range(N+1)]
d = [set() for _ in range(N+1)]
for _ in range(N-1):
    a, b = map(int, input().split())
    G[a].add(b)
    G[b].add(a)

stack = [1]
vs = set([1])
vs_dfs = list()
while stack:
    v = stack.pop()
    vs_dfs.append(v)
    for u in G[v]:
        if u in vs:
            continue
        d[v].add(u)
        vs.add(u)
        stack.append(u)
inf = 10**18
dp1 = [0]*(N+1)
dp2 = [-inf]*(N+1)
for v in vs_dfs[::-1]:
    dp2[v] = A[v]
    for u in d[v]:
        dp2[v] += max(dp1[u], dp2[u])
        dp1[v] += max(dp2[u], dp1[u] + B[u] + B[v])
print(max(dp1[1], dp2[1]))