N,M=map(int,input().split())
from collections import Counter
A=Counter([int(x)%M for x in input().split()])
ans=0
T=set()
for a in A:
	if a*2==M or a==0:
		if A[a]>=1:
			ans+=1
	else:
		if not a in T:
			ans+=max(A[a],A[M-a])
			T.add(a)
			T.add(M-a)
print(ans)