import sys
sys.setrecursionlimit(10 ** 9)

n = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
edges = [[] for _ in range(n)]
for _ in range(n - 1):
    u, v = map(int, input().split())
    u -= 1
    v -= 1
    edges[u].append(v)
    edges[v].append(u)
    
dp0 = [0] * n
dp1 = [0] * n

def dfs(pos, bpos):
    dp0[pos] = A[pos]
    for npos in edges[pos]:
        if npos == bpos:
            continue
        dfs(npos, pos)
        dp0[pos] += max(dp0[npos], dp1[npos])
        dp1[pos] += max(dp0[npos], dp1[npos] + B[pos] + B[npos])
    
dfs(0, -1)
print(max(dp0[0], dp1[0]))