#!/bin/python3

import math
import os
import random
import re
import sys

#
# Complete the 'cutTheTree' function below.
#
# The function is expected to return an INTEGER.
# The function accepts following parameters:
#  1. INTEGER_ARRAY data
#  2. 2D_INTEGER_ARRAY edges
#
sys.setrecursionlimit(10**7)

class Vertex:
    def __init__(self, value):
        self.value = value
        self.edges = []
        self.is_init = False
    
    def add_edge(self, vertex):
        self.edges.append(vertex)
        
def init(vertex, parent, sum_cache):
    vertex.is_init = True
    subtotal = vertex.value
    for adj in vertex.edges:
        if adj is not parent:
            subtree_sum = init(adj, vertex, sum_cache)
            sum_cache[(vertex, adj)] = subtree_sum
            sum_cache[(adj, vertex)] = sum_cache_total - subtree_sum
            subtotal += subtree_sum
    return subtotal

def min_diff(vertices, sum_cache, total_sum):
    min_diff_value = total_sum
    for v in vertices:
        for adj in v.edges:
            diff = abs(total_sum - 2 * sum_cache[(v, adj)])
            if diff < min_diff_value:
                min_diff_value = diff
    return min_diff_value

N = int(sys.stdin.readline())
values = list(map(int, sys.stdin.readline().split()))
vertices = [Vertex(val) for val in values]
for _ in range(N - 1):
    a, b = map(int, sys.stdin.readline().split())
    vertices[a - 1].add_edge(vertices[b - 1])
    vertices[b - 1].add_edge(vertices[a - 1])

sum_cache = {}
sum_cache_total = sum(values)
init(vertices[0], None, sum_cache)
result = min_diff(vertices, sum_cache, sum_cache_total)
print(result)