import sys
input = sys.stdin.readline
from collections import *

N, M = map(int, input().split())
A = list(map(int, input().split()))
cnt = defaultdict(int)

for Ai in A:
    cnt[Ai%M] += 1

ans = 0

for i in range(1, (M+1)//2):
    ans += max(cnt[i], cnt[M-i])

ans += min(1, cnt[0])

if M%2==0:
    ans += min(1, cnt[M//2])

print(ans)