#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  long long M;
  cin >> N >> M;
  vector<long long> A(N);
  for (int i = 0; i < N; i++){
    cin >> A[i];
  }
  set<long long> st;
  map<long long, int> mp;
  for (int i = 0; i < N; i++){
    long long r = A[i] % M;
    mp[r]++;
    r = min(r, M - r);
    st.insert(r);
  }
  int ans = 0;
  for (long long x : st){
    if (x == 0 || x * 2 == M){
      ans++;
    } else {
      ans += max(mp[x], mp[M - x]);
    }
  }
  cout << ans << endl;
}