#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 100 * 1000 + 10;
int a[MAX_N];
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  int u = k;
  for (int i = 1; i <= n; i++) {
    if (u - i > 0)
      u -= i;
    else
      break;
  }
  cout << a[u - 1] << endl;
  return 0;
}
