#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/extc++.h>
using namespace std;
using ld = long double; 
const vector<int> dx = {0, 0, 1, -1};
const vector<int> dy = {1, -1, 0, 0};
#define vec vector
#define int long long
#define double long double
//cout<<setprecision(10)<<fixed<<..
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repp(i, x, n) for (int i = x; i < (int)(n); i++)
#define pii pair<int,int>
#define pq priority_queue

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int n;cin>>n;
    int m;cin>>m;
    vec<int> cnt(m*2+1,0);
    vec<int> A(n);rep(i,n){cin>>A[i];cnt[A[i]*2]++;}
    int ans=0;

    for(int i=1;i<=m/2;i++){
        if(i>m/2.0){
            int v=2*i;
            int op=v-m;
            ans+=cnt[v]*cnt[op]*(n-cnt[v]-cnt[op]);
        }else{
            int v=2*i;
            int op=v+m;
            ans+=cnt[v]*cnt[op]*(n-cnt[v]-cnt[op]);
        }
    }
    cout<<ans;

}