#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
struct BIT {
  int bit[maxn];
  void upd(int x, int v) {
    for (; x < maxn; x += (x & -x)) bit[x] += v;
  }
  int soma(int x) {
    int ans = 0;
    for (; x > 0; x -= (x & -x)) ans += bit[x];
    return ans;
  }
} b_pref, b_suf;
int n;
long long k;
int a[maxn];
void compress(void) {
  map<int, int> mp;
  for (int i = 1; i <= n; i++) mp[a[i]] = 0;
  int aux = 0;
  for (auto &x : mp) x.second = ++aux;
  for (int i = 1; i <= n; i++) a[i] = mp[a[i]];
}
int main(void) {
  scanf("%d %lld", &n, &k);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  compress();
  long long inv = 0;
  for (int i = n; i >= 2; i--) {
    inv += 1ll * b_suf.soma(a[i] - 1);
    b_suf.upd(a[i], 1);
  }
  long long ans = 0;
  int l = 1, r = 2;
  for (; l <= n; l++) {
    inv += 1ll * (b_pref.soma(n) - b_pref.soma(a[l]));
    b_pref.upd(a[l], 1);
    inv += 1ll * b_suf.soma(a[l] - 1);
    while ((inv > k || r <= l) && r <= n) {
      inv -= 1ll * b_suf.soma(a[r] - 1);
      inv -= 1ll * (b_pref.soma(n) - b_pref.soma(a[r]));
      b_suf.upd(a[r], -1);
      ++r;
    }
    if (r <= n) ans += 1ll * (n - r + 1);
  }
  printf("%lld\n", ans);
}
