#include <iostream>
using namespace std;
long long n, c;
long long  a[20000005], m[20000005];
long long ans;
int main()
{
    cin >> n >> c;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        m[a[i]]++;
    }
    for (int i = 1; i <= n; i++)
        ans += m[c + a[i]];
    cout << ans;
    return 0;
}