#include <iostream>
#include <algorithm>

using namespace std;

long long n, k, a[100005];
int main()
{
    cin >> n >> k;
    for(int i = 0; i < n; i++) cin >> a[i];

    sort(a, a + n);

    long long cnt = 0;

    for(int i = 0; i < n; i++)
    {
        int t = lower_bound(a, a + n, k - a[i]) - a - 1;
        if(t < i) break;
        else cnt += t - i;
    }

    cout << cnt;
}