#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9;
const int N = 100010;
int n, k, m;
int a[N];
int main() {
  ios_base::sync_with_stdio(0);
  cout.tie(0);
  cin.tie(0);
  cin >> n >> k;
  for (int i = 1; i <= n; i++) cin >> a[i];
  int cnt = 0;
  while (k > 0) {
    cnt += 1;
    k -= cnt;
  }
  cout << a[k + cnt];
  return 0;
}
