mod = 1000000007
eps = 10**-9


def main():
    import sys
    from collections import deque
    input = sys.stdin.buffer.readline

    N = int(input())
    A = [0] + list(map(int, input().split()))
    B = [0] + list(map(int, input().split()))
    adj = [[] for _ in range(N+1)]
    for _ in range(N-1):
        a, b = map(int, input().split())
        adj[a].append(b)
        adj[b].append(a)

    que = deque()
    que.append(1)
    seen = [-1] * (N+1)
    seen[1] = 0
    par = [0] * (N+1)
    child = [[] for _ in range(N+1)]
    seq = []
    while que:
        v = que.popleft()
        seq.append(v)
        for u in adj[v]:
            if seen[u] == -1:
                seen[u] = seen[v] + 1
                par[u] = v
                child[v].append(u)
                que.append(u)
    seq.reverse()

    dp0 = [0] * (N+1)
    dp1 = [0] * (N+1)
    for v in seq:
        dp0[v] = A[v]
        for u in child[v]:
            dp0[v] += max(dp0[u], dp1[u])
            dp1[v] += max(dp0[u], dp1[u] + B[u] + B[v])
    print(max(dp0[1], dp1[1]))


if __name__ == '__main__':
    main()