import sys
from functools import cache

sys.setrecursionlimit(2 * 10**5 + 10)

N = int(input())
S = [int(s) for s in input().split()]

tree = [[] for _ in range(N)]
for _ in range(N - 1):
    u, v = [int(s) - 1 for s in input().split()]
    tree[u].append(v)
    tree[v].append(u)

order = sorted([*range(N)], key=lambda i: S[i])


@cache
def dp(v):
    res = 0
    for to in tree[v]:
        if S[to] <= S[v]:
            continue
        res = max(res, dp(to))

    return res + S[v]


ans = 0

for i in order:
    ans = max(ans, dp(i))

print(ans)