class A
  def initialize
    n, m = gets.chomp.split(' ').map(&:to_i)
    shaffle = gets.chomp.split(' ').map(&:to_i)
    cards = [*(1..n)]

    shaffle.each do |i|
      num = cards.delete_at(i-1)
      cards.unshift(num)
    end

    puts cards.first
  end
end

A.new