#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

int main()
{
    int n, m;
    cin >> n >> m;
    map<int, ll> mp;
    rep(i,n){
        int a;
        cin >> a;
        mp[a]++;
    }
    if(m%2==1){
        cout << 0 << endl;
        return 0;
    }
    ll ans = 0;
    for(auto p : mp){
        if(mp.count(p.first+m/2)){
            ans += n-2;
        }
        dbg(p.first);
    }
    cout << ans << endl;
    return 0;
}