N = gets.to_i
graph = Array.new(N) { [] }
(N - 1).times do
    u, v = gets.split.map { |s| s.to_i - 1}
    graph[u] << v
    graph[v] << u
end

depth = [nil] * N
depth[0] = 0
stack = [0]
while (u = stack.pop)
    graph[u].each do |v|
        next if depth[v]
        depth[v] = depth[u] + 1
        stack << v
    end
end

path = []
visited = [false] * N
dfs = ->u {
    visited[u] = true
    graph[u].each do |v|
        next if visited[v]
        path << v
        dfs[v]
        path << u
    end
}
dfs[0]

mode = -1
visited = [false] * N
ans = 4
u = path[0]
visited[u] = true
path[1..].each do |v|
    next if visited[v] or (depth[u] <=> depth[v]) != mode
    visited[v] = true
    mode = -mode
    ans += 1
    u = v
end

puts ans