//各aについて、mod M = a, M - aのうち片方しか取れない
//0, M / 2 は それぞれ1個まで。
#include <iostream>
#include <algorithm>
#include <map>
#define int long long
using namespace std;

int gcd(int a, int b) {
	if (b == 0) return a;
	return gcd(b, a % b);
}

int n, m;
int a[100000];
map<int, int> mp;

signed main() {
	int i;

	cin >> n >> m;
	for (i = 0; i < n; i++) {
		cin >> a[i];
		a[i] %= m;
		if (mp.find(a[i]) == mp.end()) mp[a[i]] = 0;
		mp[a[i]]++;
	}

	for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++) {
		int mod = it->first;
		if (mod == 0 || mod * 2 == m) { //不注意ポイント
			mp[mod] = min(mp[mod], 1LL);
		}
	}

	int pair_cnt = 0, single_cnt = 0;
	for (map<int, int>::iterator it = mp.begin(); it != mp.end(); it++) {
		int mod = it->first;
		if (mp.find(m - mod) != mp.end()) {
			pair_cnt += max(mp[mod], mp[m - mod]);
		}
		else {
			single_cnt += mp[mod];
		}
	}

	cout << pair_cnt / 2 + single_cnt << endl;
	return 0;
}