#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cassert>
#include<cmath>
#include<ctime>
#include<iomanip>
#include<numeric>
#include<stack>
#include<queue>
#include<map>
#include<unordered_map>
#include<set>
#include<unordered_set>
#include<bitset>
#include<random>
#include<functional>
#include<utility>
using namespace std;
void solve();
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int tt = 1;
	//cin >> tt;
	while(tt--) solve();
}
int N,M,A[3 << 17];
void solve()
{
	cin >> N >> M;
	set<int> S;
	for(int i = 0;i < N;i++) cin >> A[i],S.insert(--A[i]);
	if(M & 1) cout << 0 << endl;
	else
	{
		long long ans = 0;
		for(int i = 0;i < N;i++)
		{
			int B = (A[i]+M/2)%M;
			if(S.count(B)) ans += N-2;
		}
		ans /= 2;
		cout << ans << endl;
	}
}