#include <bits/stdc++.h>
using namespace std;
int n, k;
int qtd = 1;
int cnt = 1;
int ans = 0;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> k;
  int robos[n];
  for (int i = 0; i < n; i++) {
    cin >> robos[i];
  }
  while (k > qtd) {
    cnt++;
    qtd += cnt;
  }
  cout << robos[cnt - (qtd - k) - 1] << endl;
}
