import sys
input = sys.stdin.readline
from collections import Counter

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

X=Counter()

for a in A:
    X[a%M]+=1

ANS=0
USE=set()

for x in X:
    #print(x,USE)
    if x!=M/2 and x!=0 and not(x in USE):
        y=M-x

        ANS+=max(X[x],X[y])
        USE.add(x)
        USE.add(y)
    elif x==M/2:
        ANS+=1
    elif x==0:
        ANS+=1

print(ANS)