n = int(input())
s = list(map(int, input().split()))
idxes = [i for i in range(n)]
idxes.sort(key = lambda x: s[x])

e = [[] for _ in range(n)]
for _ in range(n-1):
    a, b = map(lambda x: int(x)-1, input().split())
    e[a].append(b)
    e[b].append(a)

dp = s[:]
for u in idxes:
    for v in e[u]:
        if s[v] > s[u]:
            dp[v] = max(dp[v], dp[u]+s[v])

print(max(dp))