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


D = {}
for i in range(M):
    D[i] = 0

for i in range(N):
    D[A[i] % M] += 1
        
ans = 0


for i in range(1,M//2+1):
    if i == M-i:
        if D[i]:
            ans += 1
    else:
        ans += max(D[i],D[M-i])
    #print(i,ans)
if D[0]:
    ans += 1
print(ans)
#print(D)