import sys
input = lambda: sys.stdin.readline().rstrip()
from collections import deque

N = int(input())
A = [int(a) for a in input().split()]
B = [int(a) for a in input().split()]
X = [[] for i in range(N)]
for i in range(N-1):
    x, y = map(int, input().split())
    X[x-1].append(y-1)
    X[y-1].append(x-1)

P = [-1] * N
Q = deque([0])
R = []
while Q:
    i = deque.popleft(Q)
    R.append(i)
    for a in X[i]:
        if a != P[i]:
            P[a] = i
            X[a].remove(i)
            deque.append(Q, a)

SA = [0] * N
SB = [0] * N

for i in R[::-1]:
    aa = A[i]
    bb = 0
    for j in X[i]:
        aa += max(SA[j], SB[j])
        bb += max(SA[j], SB[j] + B[i] + B[j])
    SA[i] = aa
    SB[i] = bb

print(max(SA[0], SB[0]))