#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int i, t, n, k, a;
  cin >> n;
  cin >> k;
  cin >> a;
  long long int index = 2, prev = a, sum = 0, N = n;
  for (i = 2; i <= N; i++) {
    cin >> a;
    if (sum + (index - 2) * prev - (index - 1) * (n - index) * a < k) {
      cout << i << endl;
      n--;
    } else {
      sum += (index - 2) * prev;
      prev = a;
      index++;
    }
  }
  return 0;
}
