local n = io.read("*n")
local edge = {}
for i = 1, n do
  edge[i] = {}
end
for i = 1, n - 1 do
  local a, b = io.read("*n", "*n")
  table.insert(edge[a], b)
  table.insert(edge[b], a)
end
local asked = {}
for i = 1, n do
  asked[i] = false
end
asked[1] = true
local tasks = {1}
for i = 1, n do
  local src = tasks[i]
  for j = 1, #edge[src] do
    local dst = edge[src][j]
    if not asked[dst] then
      table.insert(tasks, dst)
      asked[dst] = true
    end
  end
end
local spos = tasks[n]
local len = {}
for i = 1, n do
  len[i] = -1
end
len[spos] = 0
tasks = {spos}
for i = 1, n do
  local src = tasks[i]
  for j = 1, #edge[src] do
    local dst = edge[src][j]
    if len[dst] < 0 then
      len[dst] = len[src] + 1
      table.insert(tasks, dst)
    end
  end
end
print(2 * (n - 1) - len[tasks[n]])