import sys
sys.setrecursionlimit(10 ** 6)
n = int(input())
a = list(map(int, input().split()))
b = list(map(int, input().split()))
edges = [[] for i in range(n)]
for i in range(n - 1):
    u, v = map(int, input().split())
    edges[u - 1].append(v - 1)
    edges[v - 1].append(u - 1)
dp = [[0] * 2 for i in range(n)]
def dfs(now, prev):
    dp[now][0] = a[now]
    for nex in edges[now]:
        if nex != prev:
            dfs(nex, now)
            dp[now][0] += max(dp[nex][0], dp[nex][1])
            dp[now][1] += max(dp[nex][0], dp[nex][1] + b[now] + b[nex])
    return None
dfs(0, -1)
print(max(dp[0]))