class Calc0026
  def initialize
    args = STDIN.readlines.map { |l| l.chomp.split(/\s+/) }
    @n = args.shift.first.to_i
    @m = args.shift.first.to_i
    @shuffles = args.map { |l| l.map(&:to_i) }
  end

  def calc
    n = @n
    @shuffles.each do |shuffle|
      if shuffle.include?(n)
        n = (shuffle - [n]).first
      end
    end
    n
  end

  def run
    puts calc
  end
end

Calc0026.new.run if __FILE__ == $0