n = 500000000
d = 500000000
pre = "1\n"
100.times{
	puts "? " + n.to_s
	$stdout.flush
	d /= 2
	d = 1 if d == 0
	if gets == "1\n"
		n += d
	else
		n -= d
	end
	pre = $_
}
puts "! " + (n-$_.to_i).to_s
$stdout.flush