import sys
input = sys.stdin.buffer.readline

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

# topological順序の計算
s = []
s.append(0)
parent = [-1]*n
order = []
while s:
    x = s.pop()
    order.append(x)
    for nx in g[x]:
        if nx == parent[x]:
            continue
        parent[nx] = x
        s.append(nx)
#print(order)
order.reverse()

dp0 = [0]*n
dp1 = [0]*n
for v in order:
    p = parent[v]
    dp0[v] += A[v]
    if p != -1:
        dp0[p] += max(dp0[v], dp1[v])
        dp1[p] += max(B[p]+B[v]+dp1[v], dp0[v])
#print(dp0)
#print(dp1)
print(max(dp0[0], dp1[0]))