#include <bits/stdc++.h>
using namespace std;
long long n, k;
struct ff {
  int value, order;
} a[100010];
bool cmp(ff a, ff b) { return a.value < b.value; }
long long sum1[100010], sum2[100010];
void add(long long s[], int i, int x) {
  while (i <= n) {
    s[i] += x;
    i += i & -i;
  }
}
long long getsum(long long s[], int i) {
  long long res = 0;
  while (i > 0) {
    res += s[i];
    i -= i & -i;
  }
  return res;
}
int b[100010];
int main() {
  while (~scanf("%I64d%I64d", &n, &k)) {
    for (int i = 1; i <= n; i++) {
      scanf("%d", &a[i].value);
      a[i].order = i;
      b[i - 1] = a[i].value;
    }
    sort(b, b + n);
    int m = unique(b, b + n) - b;
    for (int i = 1; i <= n; i++) {
      a[i].order = lower_bound(b, b + m, a[i].value) - b + 1;
    }
    memset(sum1, 0, sizeof sum1);
    memset(sum2, 0, sizeof sum2);
    long long res = 0;
    long long ans = 0;
    for (int i = 1; i <= n; i++) {
      add(sum1, a[i].order, 1);
      res += i - getsum(sum1, a[i].order);
    }
    if (res <= k) {
      printf("%I64d\n", n * (long long)(n - 1) / 2);
      continue;
    }
    add(sum1, a[n].order, -1);
    add(sum2, a[n].order, 1);
    for (int l = n - 1, r = n - 1; r > 0; r--) {
      while (l > 0 && res > k) {
        res -= l - getsum(sum1, a[l].order);
        res -= getsum(sum2, a[l].order - 1);
        add(sum1, a[l].order, -1);
        l--;
      }
      if (l == 0) break;
      ans += l;
      res += getsum(sum2, a[r].order - 1);
      res += l - getsum(sum1, a[r].order);
      add(sum2, a[r].order, 1);
    }
    cout << ans << endl;
  }
  return 0;
}
