#include <bits/stdc++.h>
using namespace std;
using ll = long long;

bool bin_search(vector<int>& a, int x){
    int ok = 0;
    int ng = a.size();
    while(abs(ok - ng) > 1){
        int mid = (ok + ng) / 2;
        if(a[mid] <= x){
            ok = mid;
        }
        else{
            ng = mid;
        }
    }
    return (a[ok] == x);
}

int main(){
    int n, m;   cin >> n >> m;
    vector<int> a(n);
    for(auto& x : a){
        cin >> x;
    }
    sort(a.begin(), a.end());

    if(m & 1){
        cout << 0 << endl;
        return 0;
    }

    ll ans = 0;
    for(auto& x : a){
        if(!bin_search(a, x + m / 2)){
            continue;
        }
        ans += n - 2;
    }
    cout << ans << endl;

    return 0;
}