N, M = gets.split.map(&:to_i)
A = gets.split.map(&:to_i)

E = Array.new(N + 1) { [] }

1.upto(N) do |i|
  i.step(N, i) do |j|
    E[j] << i
  end
end

opened = Array.new(N + 1, false)

A.each do |a|
  opened[a] = true
end

ans = 0

N.downto(1) do |i|
  if opened[i]
    E[i].each do |j|
      opened[j] ^= true
    end
  else
    ans += 1
  end
end

puts ans