#include <bits/stdc++.h>
using namespace std;
struct Bit {
  int a[1020304];
  void clr() { memset(a, 0, sizeof(a)); }
  void Ins(int t, int k) {
    for (int z = t; z < 1020304; z += (z & (-z))) a[z] += k;
  }
  int ask(int p) {
    if (p == 0) return 0;
    int ret = 0;
    for (int z = p; z; z -= (z & (-z))) ret += a[z];
    return ret;
  }
  int Ask(int l, int r) { return ask(r) - ask(l - 1); }
} t1, t2;
int n, a[1020304], b[1020304];
long long K;
map<int, int> MAP;
int main() {
  cin >> n >> K;
  for (int i = 1; i <= n; ++i) scanf("%d", &a[i]), b[i] = a[i];
  sort(b + 1, b + n + 1);
  for (int i = 1; i <= n; ++i) MAP[b[i]] = i;
  for (int i = 1; i <= n; ++i) a[i] = MAP[a[i]];
  t2.clr();
  t1.clr();
  long long tNow = 0;
  for (int i = n; i >= 2; --i) {
    tNow += t2.Ask(1, a[i] - 1);
    t2.Ins(a[i], 1);
  }
  int tJ = 0;
  long long ans = 0;
  for (int i = 1; i <= n - 1; ++i) {
    while (tNow + t1.Ask(a[tJ + 1] + 1, n) + t2.Ask(1, a[tJ + 1] - 1) <= K &&
           tJ < i) {
      tNow += t1.Ask(a[tJ + 1] + 1, n) + t2.Ask(1, a[tJ + 1] - 1);
      t1.Ins(a[++tJ], 1);
    }
    ans += tJ;
    tNow -= t1.Ask(a[i + 1] + 1, n) + t2.Ask(1, a[i + 1] - 1);
    t2.Ins(a[i + 1], -1);
  }
  cout << ans << endl;
  return 0;
}
