local function query(a, b)
  io.write("? " .. a .. " " .. b .. "\n")
  io.flush()
  local ret = io.read("*l")
  return tonumber(ret)
end
local function ans(a)
  io.write("! " .. a .. "\n")
  io.flush()
end

local n = io.read()
n = tonumber(n)
local t = {}
local d = {}
d[1] = {}
for i = 1, n do
  t[i] = {}
  d[1][i] = i
end

local stage = 1
while 1 < #d[stage] do
  d[stage + 1] = {}
  for i = 1, #d[stage], 2 do
    if i ~= #d[stage] then
      local v1, v2 = d[stage][i], d[stage][i + 1]
      local ret = query(v1, v2)
      table.insert(d[stage + 1], ret)
      if v1 == ret then
        table.insert(t[v1], v2)
      else
        table.insert(t[v2], v1)
      end
    else
      table.insert(d[stage + 1], d[stage][i])
    end
  end
  stage = stage + 1
end
local top = d[stage][1]
local second = t[top][1]
for i = 2, #t[top] do
  local v = t[top][i]
  local ret = query(second, v)
  second = ret
end
ans(second)