def question(query)
  puts "? " + query.join(" ")
  STDOUT.flush
  s = gets.chomp
  return s
end

N = gets.to_i
ans = ["?"] * (2*N+1)

res_1N = question((1..N).to_a)

ok, ng = N+1, 0
while (ok - ng).abs > 1
  mid = (ok + ng)/2
  query = (mid..mid+N-1).to_a
  if res_1N != question(query)
    ok = mid
  else
    ng = mid
  end
end

rb_half = (ok..ok+N-2).to_a
rb_half2 = (1..ok-2).to_a + (ok+N..2*N).to_a

1.upto(2*N) do |i|
  target = rb_half.include?(i) ? rb_half2 : rb_half
  res = question(target + [i])
  ans[i] = res == "Red" ? "R" : "B"
end

puts "! #{ans[1, 2*N].join}"
exit