N = int(input())

G = [[] for _ in range(N+1)]
edge = []
for _ in range(N-1):
    a,b,c = map(int,input().split())
    G[a].append((b,c))
    G[b].append((a,c))
    edge.append((c,a,b))
edge.sort(reverse = True,key = lambda x:x[0])
M,u,v = edge[0]
_min = edge[0][0]
import sys
sys.setrecursionlimit(10 ** 8)
parent = [0] * (N+1)
parent[u] = (u,M)
parent[v] = (v,M)
"""
def dfs(now,p):
    for v,c in G[now]:
        if v == p:continue
        parent[v] = (now,c)
        dfs(v,now)
"""
def dfs(now,p):
    stack = [(now,p)]
    while stack:
        now,p = stack.pop()
        for v,c in G[now]:
            if v == p:continue
            parent[v] = (now,c)
            stack.append((v,now))
dfs(u,v)
dfs(v,u)
memo = [0] * (N+1)
memo[u] = 1
memo[v] = 1
for i in range(1,N-1):
    c,a,b = edge[i]
    tmp = _min
    if parent[b][0] == a:
        a,b = b,a
    d = a
    while memo[a] == 0:
        memo[a] = 1
        if parent[a][1] < tmp:
            tmp = parent[a][1]
        a = parent[a][0]
    if a != u and a != v:
        break
    if M - tmp >= c:
        break
    if u == a:
        u = d
    else:
        v = d
    _min = tmp
while parent[v][0] != v:
    parent[v] = (parent[v][0],parent[v][1] - _min)
    v = parent[v][0]
while parent[u][0] != u:
    parent[u] = (parent[u][0],parent[u][1] - _min)
    u = parent[u][0]
parent[u] = (parent[u][0],parent[u][1] - _min)
parent[v] = (parent[v][0],parent[v][1] - _min)
ans = 0
for i in range(1,N+1):
    if parent[i][1] > ans:
        ans = parent[i][1]
print(ans)