import sys
def input():
	return sys.stdin.buffer.readline()[:-1]

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

dp = [[0 for _ in range(2)] for _ in range(n)]
visited = [False for _ in range(n)]

stack = [(0, -1)]
while stack:
	i, p = stack[-1]
	if not visited[i]:
		visited[i] = True
		for j in adj[i]:
			if j != p:
				stack.append((j, i))
	else:
		stack.pop()
		dp[i][0] = a[i]
		for j in adj[i]:
			if j != p:
				dp[i][0] += max(dp[j][0], dp[j][1])
				dp[i][1] += max(dp[j][0], dp[j][1] + b[i] + b[j])

print(max(dp[0]))