n = int(input())
A = list(map(int, input().split()))
dp = A[:]
node = [[] for _ in range(n)]
for _ in range(n-1):
    u, v = list(map(lambda x: int(x)-1, input().split()))
    node[u].append(v)
    node[v].append(u)

I = [i for i in range(n)]
I.sort(key = lambda x: A[x])
for u in I:
    for v in node[u]:
        if A[v] > A[u]:
            dp[v] = max(dp[v], dp[u]+A[v])
print(max(dp))