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

  cnt_1 = (M % (i + i) == 0) ? [1, counter[i]].min : counter[i]
  cnt_2 = (M % (j + j) == 0) ? [1, counter[j]].min : counter[j]
  ans += [cnt_1, cnt_2].max
end

puts ans