class Calc0123
  def initialize(args)
    args = args.map { |l| l.chomp.split(/\s+/) }
    @n, @m = args.shift.first.to_i
    @as = args.shift.map(&:to_i)
  end

  def run
    cards = (1..@n).to_a
    @as.each do |a|
      c = cards[a - 1]
      case a
      when 1
        # nop
      when @n
        cards = [c] + cards[0..-2]
      else
        cards = [c] + cards[0..(a - 2)] + cards[a..-1]
      end
    end
    cards.first
  end
end

puts Calc0123.new(STDIN.readlines).run if __FILE__ == $0