n, m = map(int, input().split())
cnt = [0]*m
for v in map(int, input().split()): cnt[v%m] += 1
ans = 0
for i in range(m//2+1):
    if i*2%m == 0: ans += min(cnt[i], 1)
    else: ans += max(cnt[i], cnt[m-i])
print(ans)