#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll=long long;
using Graph=vector<vector<int>>;
#define INF 1000000000000000000
#define MOD 998244353
#define MAX 500

int main(){
  int N;
  ll M;
  cin>>N>>M;
  map<ll,int> m;
  for(int i=0;i<N;i++){
    ll A;
    cin>>A;
    m[A%M]++;
  }

  ll ans=0;
  for(auto p:m){
    if(2*p.first==M&&p.second>0){
      ans++;
    }else{
      if(p.second>=m[M-p.first]){
        ans+=p.second;
        m[M-p.first]=0;
      }
    }
  }
  cout<<ans<<'\n';
}