import sys
from collections import deque

input = sys.stdin.buffer.readline


def bfs(N, T, v0):
    dist = [None] * N
    dist[v0] = 0
    d = deque([v0])
    while d:
        v = d.popleft()
        dx = dist[v] + 1
        for x in T[v]:
            if dist[x] is None:
                dist[x] = dx
                d.append(x)
    max_dist = max(dist)
    return dist.index(max_dist), max_dist


def calc_diameter(N, T):
    u, _ = bfs(N, T, 0)
    v, diameter = bfs(N, T, u)
    return diameter


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

print(2 * (N - 1) - calc_diameter(N, T))