#include <bits/stdc++.h>
using namespace std;
const int MAX = 1e5 + 10;
const int MAXN = 1e4 + 10;
const int MOD = 1e9 + 7;
const int inf = 1e9;
const double pi = acos(-1.0);
const double eps = 1e-6;
int a[MAX];
int main() {
  ios::sync_with_stdio(false);
  int n;
  long long k, lo, hi, mi, res;
  cin >> n >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  lo = 1;
  hi = n;
  while (lo <= hi) {
    mi = (lo + hi) / 2;
    if (mi * (mi + 1) >= k * 2) {
      res = mi;
      hi = mi - 1;
    } else
      lo = mi + 1;
  }
  res = res * (res - 1) / 2;
  cout << a[k - res - 1];
  return 0;
}
