import sys
input = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 7)

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


def dfs(r):
    d = [-1] * N
    d[r] = 0
    que = [r]
    while que:
        s = que.pop()
        for t in G[s]:
            if d[t] == -1:
                d[t] = d[s] + 1
                que.append(t)
    return d


d1 = dfs(0)
r = d1.index(max(d1))
d2 = dfs(r)
print(N - max(d2) - 1)