## https://yukicoder.me/problems/no/806

from collections import deque

MAX_INT = 10 ** 18


def dijkstra(N, next_nodes, start):
    dists = [MAX_INT] * N
    queue = deque()

    dists[start] = 0
    queue.append(start)
    while len(queue) > 0:
        v = queue.popleft()

        for w in next_nodes[v]:
            if dists[w] == MAX_INT:
                dists[w] = dists[v] + 1
                queue.append(w)
    return dists

def main():
    N = int(input())
    next_nodes = [[] for _ in range(N)]
    for _ in range(N -  1):
        a, b  = map(int ,input().split())
        next_nodes[a - 1].append(b - 1)
        next_nodes[b - 1].append(a - 1)
    
    dists = dijkstra(N, next_nodes, 0)

    target_i = -1
    target_dist = -1
    for i in range(N):
        if target_dist < dists[i]:
            target_dist = dists[i]
            target_i = i

    dists = dijkstra(N, next_nodes, target_i)

    diag = max(dists)
    print(N - (diag + 1))




                




if __name__ == "__main__":
    main()