# # 1220 生命之树
# 状态表示数组和深度优先搜索,把节点的空间开到合适n*2,把节点的index搞清楚
n = int(input())
w = list(map(int, input().split()))
N = n

e = [0] * (2 * n)
ne = [0] * (2 * n)
cnt = 0
h = [-1] * (2 * n)

def add(a, b):
    global cnt
    e[cnt] = b
    ne[cnt] = h[a]
    h[a] = cnt
    cnt += 1

while(N - 1):
    a, b = map(int, input().split())
    add(a - 1, b - 1)
    add(b - 1, a - 1)
    N -= 1

q = [0] * (n + 10)

def dfs(a, father):
    q[a] = w[a]
    buf = h[a]
    while(buf != -1):
        if e[buf] != father:
            dfs(e[buf], a)
            q[a] += max(0, q[e[buf]])
        buf = ne[buf]


dfs(0, -1)
ans = q[0]
for i in range(1, n):
    ans = max(ans, q[i])
print(ans)