import sys
import pypyjit
import itertools
import heapq
import math
from collections import deque, defaultdict
import bisect

input = sys.stdin.readline
sys.setrecursionlimit(10 ** 6)
pypyjit.set_param('max_unroll_recursion=-1')


def index_lt(a, x):
    'return largest index s.t. A[i] < x or -1 if it does not exist'
    return bisect.bisect_left(a, x) - 1


def index_le(a, x):
    'return largest index s.t. A[i] <= x or -1 if it does not exist'
    return bisect.bisect_right(a, x) - 1


def index_gt(a, x):
    'return smallest index s.t. A[i] > x or len(a) if it does not exist'
    return bisect.bisect_right(a, x)


def index_ge(a, x):
    'return smallest index s.t. A[i] >= x or len(a) if it does not exist'
    return bisect.bisect_left(a, x)


N = int(input())
E = [[] for _ in range(N)]
for _ in range(N - 1):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    E[a].append(b)
    E[b].append(a)


def search(s):
    dq = deque([s])
    INF = 1 << 30
    cost = [INF] * N
    cost[s] = 0

    while len(dq) > 0:
        v = dq.popleft()
        for d in E[v]:
            if cost[d] > cost[v] + 1:
                cost[d] = cost[v] + 1
                dq.append(d)
    return cost


c = search(0)
s = 0
for i in range(N):
    if c[s] < c[i]:
        s = i
c = search(s)
t = 0
for i in range(N):
    if c[t] < c[i]:
        t = i
print(N - 1 - c[t])