#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, a = 1;
  cin >> n >> k;
  int arr[n];
  for (int i = 0; i < n; i++) cin >> arr[i];
  for (int i = 0; i < n; i++) {
    a += i;
    if (a > k) {
      a -= i;
      return cout << arr[k - a], 0;
    }
  }
  return cout << arr[k - a], 0;
}
