#include <bits/stdc++.h>
using namespace std;
int INP, AM, REACHEOF;
char BUF[(1 << 12) + 1], *inp = BUF;
const long double PI = acos((long double)-1.0);
const int MN = 100111;
int n, a[MN], c[MN], f1[MN], f2[MN], sl;
long long k;
void update(int f[], int u, int k) {
  f[u] += k;
  int v = u + ((u) & (-(u)));
  if (v <= sl) update(f, v, k);
}
int get(int f[], int u) {
  if (u <= 0) return 0;
  return f[u] + get(f, u - ((u) & (-(u))));
}
int main() {
  while (cin >> n >> k) {
    for (int i = (1), _b = (n); i <= _b; i++) {
      scanf("%d", &a[i]);
      c[i] = a[i];
    }
    sort(c + 1, c + n + 1);
    sl = unique(c + 1, c + n + 1) - c - 1;
    for (int i = (1), _b = (n); i <= _b; i++)
      a[i] = lower_bound(c + 1, c + sl + 1, a[i]) - c;
    long long inv = 0;
    memset(f1, 0, sizeof f1);
    memset(f2, 0, sizeof f2);
    for (int i = (n), _b = (1); i >= _b; i--) {
      inv += get(f2, a[i] - 1);
      update(f2, a[i], 1);
    }
    if (inv <= k) {
      cout << n * (n - 1LL) / 2 << endl;
      continue;
    }
    int r = 2;
    long long res = 0;
    update(f2, a[1], -1);
    for (int l = (1), _b = (n); l <= _b; l++) {
      if (l > 1) {
        inv += l - 1 - get(f1, a[l]);
        inv += get(f2, a[l] - 1);
      }
      update(f1, a[l], 1);
      while (r < n && inv > k) {
        inv -= l - get(f1, a[r]);
        inv -= get(f2, a[r] - 1);
        update(f2, a[r], -1);
        ++r;
      }
      if (inv <= k) {
        res += n - r + 1;
      }
    }
    cout << res << endl;
  }
  return 0;
}
