#include <bits/stdc++.h>
using namespace std;
vector<int> v[200001];
long long visited[200006];
set<long long> set1[200001];
int N;
string s;
long long arr[200005];
long long Pri[3030303];
bool prime[3030303];
int main() {
  long long N, M;
  long long i, j, k, a, b, l;
  cin >> N >> k;
  for (i = 1; i < N + 1; i++) cin >> arr[i];
  j = 1;
  if (k == 1) {
    cout << arr[1] << endl;
    return 0;
  }
  while (1) {
    a = (j * (j + 1) / 2) + 1;
    b = ((j + 1) * (j + 2) / 2);
    if (k <= b && k >= a) break;
    j++;
  }
  k = k - ((j * (j + 1)) / 2);
  l = k % (j + 2);
  cout << arr[l] << endl;
}
