#include <bits/stdc++.h>
using namespace std;
long long id[100001];
int main(void) {
  long long n, k, ans;
  cin >> n >> k;
  for (int i = 0; i < n; i++) cin >> id[i];
  long long start = 1;
  long long end = n;
  long long exact = 0, mid = -1;
  while (start <= end) {
    mid = (start + end) / 2;
    ans = (mid) * (mid + 1);
    if (ans < 2 * k)
      start = mid + 1;
    else if (ans == 2 * k) {
      exact = 1;
      break;
    } else
      end = mid - 1;
  }
  long long now = -1;
  if (start > end) {
    now = end;
    long long res = k - now * (now + 1) / 2;
    cout << id[res - 1];
  } else if (exact) {
    cout << id[mid - 1];
  }
  return 0;
}
