import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = (1 << 63)-1
inf = (1 << 31)-1
# md = 10**9+7
md = 998244353

n = II()
to = [[] for _ in range(n)]
cc = [0]
ci = [(0, 0)]
for i in range(1, n):
    u, v, c = LI1()
    to[u].append((v, i))
    to[v].append((u, i))
    cc.append(c+1)
    ci.append((c+1, i))
ci.sort()
mx = ci[-1][0]
# pDB(ci)

ep = [-1]*n
ed = [0]*n
st = [(0, 0)]
while st:
    u, pi = st.pop()
    for v, i in to[u]:
        if i == pi: continue
        ep[i] = pi
        ed[i] = ed[pi]+1
        st.append((v, i))
# pDB(ep, ed)

def binary_search(l, r, ok, minimize):
    if minimize: l -= 1
    else: r += 1
    while l+1 < r:
        m = (l+r)//2
        if ok(m) ^ minimize: l = m
        else: r = m
    if minimize: return r
    return l

from bisect import bisect_right
from collections import Counter

def ok(m):
    si = bisect_right(ci, (m, n+1))
    use = set()
    di = []
    dcnt = Counter()
    for _, i in ci[si:]:
        use.add(i)
        d = ed[i]
        di.append((d, i))
        if dcnt[d] == 2: return False
        dcnt[d] += 1

    di.sort(key=lambda x: -x[0])
    if len(di) > 2 and di[1][0] == di[2][0]:
        if di[0][0] != di[1][0]+1: return False
        i, j = di[0][1], di[2][1]
        if ep[i] != j: di[1], di[2] = di[2], di[1]
        j = di[2][1]
        if ep[i] != j: return False

    d0, i = di[0]
    d1, j = di[1]
    mn = cc[i]

    def move(i, mn):
        if i in use: use.remove(i)
        i = ep[i]
        mn = min(mn, cc[i])
        return i, mn

    for _ in range(d0-d1):
        i, mn = move(i, mn)
        if mx-mn > m: return False

    if i == j:
        a = di[-1][1]
        while i != a:
            i, mn = move(i, mn)
            if mx-mn > m: return False
        use.remove(a)
    else:
        while 1:
            i, mn = move(i, mn)
            j, mn = move(j, mn)
            if i==j:break
            if mx-mn > m: return False

    return len(use) == 0

ans = binary_search(0, ci[-2][0], ok, True)
print(ans)