#include <bits/stdc++.h>
using namespace std;
const int nMax = 100010;
int a[nMax], b[nMax], s[nMax * 3], s2[nMax * 3];
void Modify(int* c, int x, int y) {
  while (x < nMax * 3 - 1) {
    c[x] += y;
    x += x & (-x);
  }
}
int getsum(int* c, int x) {
  int res = 0;
  while (x) {
    res += c[x];
    x -= x & (-x);
  }
  return res;
}
int main() {
  long long sum, k, ans;
  int n, m, ta, he, i;
  while (scanf("%d%I64d", &n, &k) != EOF) {
    m = 0;
    sum = 0;
    ans = 0;
    memset(s, 0, sizeof(s));
    memset(s2, 0, sizeof(s2));
    for (i = 1; i <= n; i++) scanf("%d", a + i), b[m++] = a[i];
    sort(b, b + m);
    m = unique(b, b + m) - b;
    for (i = 1; i <= n; i++) a[i] = lower_bound(b, b + m, a[i]) - b + 1;
    for (i = 1; i <= n; i++) {
      Modify(s, a[i], 1);
      sum += i - getsum(s, a[i]);
    }
    if (sum <= k) {
      printf("%I64d\n", (long long)n * (n - 1) / 2);
      continue;
    }
    he = n - 1, ta = n;
    Modify(s, a[n], -1);
    Modify(s2, a[n], 1);
    while (1) {
      while (sum > k && he) {
        sum -= he - getsum(s, a[he]);
        sum -= getsum(s2, a[he] - 1);
        Modify(s, a[he], -1);
        he--;
      }
      if (!he) break;
      ans += he;
      ta--;
      sum += he - getsum(s, a[ta]);
      sum += getsum(s2, a[ta] - 1);
      Modify(s2, a[ta], 1);
    }
    printf("%I64d\n", ans);
  }
  return 0;
}
