import sys
def input():
	return sys.stdin.buffer.readline()[:-1]
sys.setrecursionlimit(10**6)

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, b[u-1] + b[v-1]))
	adj[v-1].append((u-1, b[u-1] + b[v-1]))

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

def dfs(i, p):
	dp[i][0] = a[i]
	for j, e in adj[i]:
		if j == p:
			continue
		dfs(j, i)
		dp[i][0] += max(dp[j][0], dp[j][1])
		dp[i][1] += max(dp[j][0], dp[j][1] + e)
	return

dfs(0, -1)
#print(*dp, sep="\n")
print(max(dp[0]))