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