Minimax

from sys import maxsize
import time

start = time.time()


data = open('data.txt', 'r')

n = int(data.readline())
tree = [[[], 0] for i in range(n + 1)]
edges = []
for i in range(n - 1):
    a, b, c = map(int, data.readline().split())
    tree[a][0].append([b, c])
    edges.append([a, b, c])


def set_vertex_price(tree, vertex_num):
    if tree[vertex_num][0] == []:
        tree[vertex_num][1] = 0
        return 0
    else:
        vertex_price = 0
        for neighbor in tree[vertex_num][0]:
            vertex_price += set_vertex_price(tree, neighbor[0]) + neighbor[1]
        tree[vertex_num][1] = vertex_price
        return vertex_price


set_vertex_price(tree, 1)
min_cost = maxsize
arg_min_cost = []
for edge in edges:
    temp_cost = max(tree[1][1] - tree[edge[1]][1] - edge[2], tree[edge[1]][1])

    if temp_cost <= min_cost:
        min_cost = temp_cost
        arg_min_cost = edge

print(min_cost)
end = time.time()
# print(end - start)
# print(arg_min_cost)