n = read_line.to_i
g = Array.new(n) { [] of Int32 }
flag = [false] * n
n.pred.times do
  a, b = read_line.split.map &.to_i.pred
  g[a] << b
  flag[b] = true
end

def dfs(v : Int32, dist : Int32, g : Array(Array(Int32)))
  res = (1..dist).sum
  g[v].each do |u|
    res += dfs(u, dist + 1, g)
  end
  res
end

puts dfs(flag.index(false).not_nil!, 0, g)