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

from collections import defaultdict
d = defaultdict(int)
for a in A:
    d[a % M] += 1
ans = N
tmp = 0
for a,v in d.items():
    if a == 0:
        ans -= v - 1
    elif M - a in d:
        u = min(v,d[M - a])
        tmp += u
if M % 2 == 0 and M // 2 in d:
    v = d[M // 2]
    ans += 1
print(ans - tmp // 2)