N, M = map(int, input().split())
A = list(map(int, input().split()))
X = [0] * M
for a in A:
    X[a % M] += 1
ans = 0
for i in range(M // 2 + 1):
    if i == 0:
        ans += min(1, X[0])
    elif i == M//2:
        if M % 2 == 0:
            ans += min(1, X[M // 2])
        else:
            ans += max(X[i], X[M - i])
    else:
        ans += max(X[i], X[M - i])
print(ans)