until (n = gets.to_i).zero?
  a = gets.split.map(&:to_i).sort{|a, b| b <=> a}
  b = gets.split.map(&:to_i).sort{|a, b| b <=> a}
  answer = nil
  win = 0
  n.times do |i|
    win += a[i] > b[i] ? 1 : 0
    next unless win > (i + 1) / 2
    answer = i + 1
    break;
  end
  puts answer ? answer : "NA"
end