#include <bits/stdc++.h>
using namespace std;
vector<int> v;
int k;
inline long long count(const long long ed) { return (ed * (ed + 1) / 2); }
int bs() {
  long long st = 1, ed = v.size(), best = -1;
  while (st <= ed) {
    long long mid = st + (ed - st) / 2;
    if (count(mid) >= k) {
      best = mid;
      ed = mid - 1;
    } else
      st = mid + 1;
  }
  return best;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n >> k;
  v.resize(n);
  for (int &i : v) {
    cin >> i;
  }
  for (int i = 1; i <= n; ++i) {
    if (k > i)
      k -= i;
    else
      return cout << v[k - 1] << '\n', 0;
  }
  return 0;
}
