#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll N,M; cin >> N >> M;
    map<ll,ll> mp;
    rep(i,N) {
        ll a; cin >> a;
        mp[a % M]++;
    }

    ll ans = 0;
    vector<ll> v;
    for(auto [x, _] : mp) v.push_back(x);
    map<ll,ll> visited;
    for(ll x : v) {
        if(visited.count(x)) continue;
        visited[x] = 1;
        visited[M - x] = 1;
        ans += max(mp[x], mp[M - x]);
    }
    cout << ans << endl;
}