#include <bits/stdc++.h>
using namespace std;
const int N = 1000 * 100 + 10;
int n, a[N];
long long k;
struct FenwickTree {
  vector<int> fen;
  FenwickTree(int n = 0) { fen.resize(n + 1, 0); }
  void upd(int x, int w = +1) {
    for (; x <= n; x += x & (-x)) fen[x] += w;
  }
  int get(int x) {
    int res = 0;
    for (; x; x -= x & (-x)) res += fen[x];
    return res;
  }
  int get(int l, int r) { return get(r) - get(l - 1); }
} prv, nxt;
int main() {
  ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  cin >> n >> k;
  vector<int> all;
  for (int i = 1; i <= n; i++) cin >> a[i], all.push_back(a[i]);
  sort(all.begin(), all.end());
  all.resize(unique(all.begin(), all.end()) - all.begin());
  for (int i = 1; i <= n; i++)
    a[i] = lower_bound(all.begin(), all.end(), a[i]) - all.begin() + 1;
  long long inv = 0, ans = 0;
  nxt = prv = FenwickTree(n);
  for (int i = n; i >= 2; i--) {
    inv += nxt.get(a[i] - 1);
    nxt.upd(a[i]);
  }
  int r = 2;
  for (int l = 1; l < n; l++) {
    inv += nxt.get(a[l] - 1);
    inv += prv.get(a[l] + 1, n);
    prv.upd(a[l]);
    while (inv > k && r <= n) {
      nxt.upd(a[r], -1);
      inv -= nxt.get(a[r] - 1);
      inv -= prv.get(a[r] + 1, n);
      r++;
    }
    if (l == r) return cout << 1LL * n * (n - 1) / 2 << '\n', 0;
    ans += n - r + 1;
  }
  cout << ans << '\n';
  return 0;
}
