n, m = map(int, input().split())
a = list(map(int, input().split()))

if m == 1:
  print("1")
  exit()

cnt = {}
for i in range(n):
  x = a[i] % m
  cnt[x] = cnt.get(x, 0) + 1

ans = 0
used = {}
for x in cnt.keys():
  y = m - x
  if not used.get(x, None) is None or not used.get(y, None) is None:
    continue

  used[x] = True
  used[y] = True
  if x == y:
    ans += 1
  else:
    ans += max(cnt.get(x, 0), cnt.get(y, 0))

print(ans)