#include <bits/stdc++.h>
using namespace std;
int dir[] = {0, 1, 0, -1, 1, 0, -1, 0};
void solve() {
  int n, k;
  cin >> n >> k;
  vector<int> id(n + 1);
  for (int i = 1; i <= n; i++) cin >> id[i];
  for (int i = 1; i <= n; i++) {
    if (i >= k) {
      cout << id[k] << endl;
      return;
    }
    k -= i;
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  int t = 1;
  for (int cn = 1; cn <= t; cn++) {
    solve();
  }
  return 0;
}
