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
checked = Hash.new(false)

counter.each do |i, cnt|
  j = M - i
  next if checked[j]
  checked[i] = true
  checked[j] = true

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

puts ans