n,m=list(map(int,input().split()))
seq=list(map(int,input().split()))
cnt=0
am=[0]*m
for i in range(len(seq)):
    sur=seq[i]%m
    am[sur]+=1
    
if am[0]>0:
    cnt+=1
    
if m%2==0:
    if am[int(m/2)]>0:
        cnt+=1
    for i in range(1,int(len(am)/2)):
        cnt+=max(am[i],am[len(am)-i])
    
else:
    for i in range(1,int(len(am)/2)+1):
        cnt+=max(am[i],am[len(am)-i])
        
print(cnt)