#include <bits/stdc++.h>
using namespace std;
int n, a[100010];
int b[100010], lb;
long long int k;
int big[100010], small[100010];
int lowbit(int x) { return x & -x; }
void addbig(int x, int y) {
  while (x) {
    big[x] += y;
    x -= lowbit(x);
  }
}
int querybig(int x) {
  int res = 0;
  while (x <= lb) {
    res += big[x];
    x += lowbit(x);
  }
  return res;
}
void addsmall(int x, int y) {
  while (x <= lb) {
    small[x] += y;
    x += lowbit(x);
  }
}
int querysmall(int x) {
  int res = 0;
  while (x) {
    res += small[x];
    x -= lowbit(x);
  }
  return res;
}
int main() {
  scanf("%d%I64d", &n, &k);
  for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
    b[i] = a[i];
  }
  sort(b, b + n);
  lb = unique(b, b + n) - b;
  for (int i = 0; i < n; i++) a[i] = lower_bound(b, b + lb, a[i]) - b + 1;
  long long int w = 0;
  memset(big, 0, sizeof(big));
  for (int i = 0; i < n; i++) {
    w += querybig(a[i] + 1);
    addbig(a[i], 1);
  }
  if (w <= k) {
    printf("%I64d\n", n * (n - 1LL) / 2);
    return 0;
  }
  long long int ans = 0;
  memset(big, 0, sizeof(big));
  memset(small, 0, sizeof(small));
  for (int i = 1; i < n; i++) addsmall(a[i], 1);
  int l = 0, r = 1;
  for (; l < n; l++) {
    if (l > 0) {
      w += querybig(a[l] + 1);
      w += querysmall(a[l] - 1);
    }
    addbig(a[l], 1);
    while (w > k && r < n) {
      w -= querybig(a[r] + 1);
      w -= querysmall(a[r] - 1);
      addsmall(a[r], -1);
      r++;
    }
    if (r >= n) break;
    ans += n - r;
  }
  printf("%I64d\n", ans);
  return 0;
}
