from collections import defaultdict
n,m = map(int,input().split())
a = list(map(int,input().split()))
b = [num%m for num in a]

d = defaultdict(int)
ans = 0
for num in b:
    if num == 0:
        ans |= 1
    else:
        d[num] += 1

for num in b:
    ans += max(d[num],d[m-num])
    d[num] = 0
    d[m-num] = 0

print(ans)