#include <bits/stdc++.h>
using namespace ::std;
const long long maxn = 1e5 + 500;
const long long mod = 1e9 + 7;
const long long inf = 1e9 + 500;
long long fen[maxn][2];
long long a[maxn];
set<long long> st;
map<long long, long long> ml;
void update(long long x, long long val, bool q) {
  x++;
  while (x < maxn) {
    fen[x][q] += val;
    x += (x & (-x));
  }
}
long long finds(long long x, bool q) {
  long long ans = 0;
  x++;
  while (x > 0) {
    ans += fen[x][q];
    x -= (x & (-x));
  }
  return ans;
}
int main() {
  long long n, k;
  cin >> n >> k;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
  }
  {
    for (long long i = 0; i < n; i++) {
      st.insert(a[i]);
    }
    long long koo = 0;
    for (set<long long>::iterator it = st.begin(); it != st.end(); it++) {
      ml[(*it)] = koo;
      koo++;
    }
    for (long long i = 0; i < n; i++) {
      a[i] = ml[a[i]];
    }
    st.clear();
    ml.clear();
  }
  long long p = 0;
  long long inv = 0;
  long long ans = 0;
  for (long long i = n - 1; i >= 0; i--) {
    update(a[i], 1, 1);
    inv += finds(a[i] - 1, 1);
  }
  if (inv <= k) {
    cout << n * (n - 1) / 2;
    return 0;
  }
  update(a[0], -1, 1);
  inv -= finds(a[0] - 1, 1);
  for (long long i = 1; i < n; i++) {
    while (inv <= k) {
      inv += finds(a[p] - 1, 1);
      inv += p - finds(a[p], 0);
      update(a[p], 1, 0);
      p++;
    }
    if (p > 0) {
      p--;
      update(a[p], -1, 0);
      inv -= finds(a[p] - 1, 1);
      inv -= p - finds(a[p], 0);
    }
    ans += p;
    update(a[i], -1, 1);
    inv -= finds(a[i] - 1, 1);
    inv -= p - finds(a[i], 0);
  }
  cout << endl << ans;
}
