from collections import Counter
n, m = map(int, input().split())
a = list(map(int, input().split()))
for i in range(n):
    a[i] %= m
c = Counter(a)
ans = 0
st = set()
for k, v in c.items():
    if k * 2 != m and m - k not in st:
        st.add(k)
        ans += max(v, c[m - k])
if m % 2 == 0 and c[m // 2] > 0:
    ans += 1
print(ans)