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])