N = gets.to_i

def send_query(k)
  STDOUT.puts("? #{k}")
  STDOUT.flush

  s = gets.to_i
  rs = k - s

  s - rs
end

s_1 = send_query(1)
s_n_1 = send_query(N - 1)

if s_1 == s_n_1
  puts "! #{2} #{N - 1}"
  exit
end

l = 2
r = N - 1

18.times do
  k = (l + r) / 2
  s = send_query(k)

  if s == 0
    if k < N / 2
      puts "! #{k + 1} #{N}"
    else
      puts "! 1 #{k}"
    end

    exit
  elsif s_1 * s < 0
    r = k
  elsif s_1 * s > 0
    l = k
  elsif s_n_1 * s < 0
    l = k
  elsif s_n_1 * x > 0
    r = k
  end
end