from collections import deque

n=int(input())
a=list(map(int,input().split()))
b=list(map(int,input().split()))
v=[[] for i in range(n)]
for i in range(n-1):
    q,w=map(int,input().split());q-=1;w-=1
    v[q].append(w);v[w].append(q)
f=deque([(0,0,0)]);dp=[[0]*2 for i in range(n)]
while f:
    q,w,e=f.pop()
    if len(v[q])>e:
        f.append((q,w,e+1))
        if v[q][e]!=w:
            f.append((v[q][e],q,0))
    else:
        dp[q]=[a[q],0]
        for i in v[q]:
            if i==w:
                continue
            dp[q][0]+=max(dp[i])
            dp[q][1]+=max(dp[i][0],dp[i][1]+b[i]+b[q])
print(max(dp[0]))