#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int N,M;
  cin>>N>>M;
  vector<int> S(M);
  for(int i=0;i<N;i++){
      int a;
      cin>>a;
      S[a%M]++;
  }
  int ans = (S[0] != 0);
  for(int i=1;M-i>=i;i++){
      ans += max(S[i],S[M-i]);
  }
  cout<<ans<<endl;
}