from collections import defaultdict
n,m=map(int,input().split())
a=list(map(int,input().split()))
d=defaultdict(int)
for i in range(n):
  d[a[i]%m]+=1
ans=0
if d[0]:
  ans+=1
for i in range(1,m):
  if i*2==m:
    if d[i]:
      ans+=1
  else:
    ans+=max(d[i],d[m-i])
    d[i]=0
    d[m-i]=0
print(ans)