from collections import defaultdict

n, m = map(int, input().split())
A = list(map(int, input().split()))

RD = defaultdict(int)
for i in range(n):
    RD[A[i] % m] += 1

R = sorted(RD.keys())
ans = 0
for r in R:
    if RD[r] == 0:
        continue
    if r == 0:
        ans += min(1, RD[r])
        continue
    if r == m // 2:
        if m % 2 == 0:
            ans += min(1, RD[r])
            continue
    ans += max(RD[r], RD[m - r])
    RD[r] = 0
    RD[m - r] = 0
print(ans)