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

counter = A.map { |a| a % M }.tally
counter.default = 0

ans = [1, counter[0]].min

1.upto(M / 2) do |i|
  j = M - i
  g1 = i.gcd(M)
  g2 = j.gcd(M)

  cnt_1 = [counter[i], M / g1 - 1].min
  cnt_2 = [counter[j], M / g2 - 1].min
  ans += [cnt_1, cnt_2].max
end

puts ans