import sys
# input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
"""
5 * 5 * 6


"""


n = ni()
s = na()
g = [[] for i in range(n)]
for _ in range(n-1):
    a, b = na()
    a -= 1
    b -= 1
    g[a].append(b)
    g[b].append(a)

dp = [s[i] for i in range(n)]

idx = sorted(range(n), key = lambda i : s[i])

for i in idx:
    for j in g[i]:
        if s[j] < s[i]:
            # print(j + 1, i + 1)
            dp[i] = max(dp[i], dp[j] + s[i])

# print(idx)
# print(dp)
print(max(dp))