import sys
readline = sys.stdin.readline

def non_rec_dfs(s):
    stack = []
    stack.append(~s)
    stack.append(s)
    par = [-1] * N
    dp0 = [0] * N
    dp1 = [0] * N
    while stack:
        u = stack.pop()
        if u >= 0:
            stack.append(~u)
            flag = 1
            for v in G[u]:
                if v == par[u]:
                    continue
                par[v] = u
                stack.append(v)
                flag = 0
        else:
            u = ~u
            if par[u] == -1:
                continue
            p = par[u]
            dp0[p] = max(dp0[p] + dp0[u] + A[u], dp0[p] + dp1[u])
            dp1[p] = max(dp1[p] + dp0[u] + A[u], dp1[p] + dp1[u] + B[u] + B[p])
    # print(dp0)
    # print(dp1)
    return max(dp0[0] + A[0], dp1[0])

N = int(readline())
A = list(map(int, readline().split()))
B = list(map(int, readline().split()))

G = [[] for i in range(N)]
for i in range(N - 1):
    u, v = map(int, readline().split())
    u, v = u - 1, v - 1
    G[u].append(v)
    G[v].append(u)
    
print(non_rec_dfs(0))