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

dict = {}

for i,v in enumerate(A):
    tmp =v%M
    if tmp not in dict:
        dict[tmp] = 1
    else:
        dict[tmp]+=1

tmp = []

for i,v in dict.items():
    tmp.append([v,i])

tmp.sort()
tmp.reverse()

#print(tmp)

ans = 0
#print(dict)
for i,v in enumerate(tmp):
    a,b = v[0],v[1]

    if b*2 == M:
        ans+=1
    else:
        #print("a=",a,"b=",b)
        #print("dict[b]",dict[b])
        ans+=dict[b]
        dict[M-b] = 0

print(ans)