# Here your code !
l = 1
h = 10 ** 9


100.times do |i|
    o = (l + h + 1).div(2)
    puts "? #{o}"
    $stdout.flush
    
    if gets.to_i == 0
        h = o - 1
    else
        l = o
    end
    if l == h
        break 
    end
end

puts "! #{Random.rand(l..h)}"
$stdout.flush