#include <bits/stdc++.h>
using namespace std;
int main() {
  vector<long long> id;
  long long n, k, m, p, c = 0, ct = 0;
  cin >> n >> k;
  if (n == 1) {
    long long t;
    cin >> t;
    cout << t << endl;
  } else if (n == 2) {
    for (long long x = 0; x < n; x++) {
      long long i;
      cin >> i;
      id.push_back(i);
    }
    if (k == 1)
      cout << id[0] << endl;
    else if (k == 2)
      cout << id[0] << endl;
    else
      cout << id[1] << endl;
  } else {
    for (long long x = 0; x < n; x++) {
      long long i;
      cin >> i;
      id.push_back(i);
    }
    while (1) {
      c++;
      m = (c * (c + 1)) / 2;
      if (k <= m) {
        if (k == m) {
          cout << id[c - 1] << endl;
          ct++;
        } else {
          long long o = ((c - 1) * c) / 2;
          if (k % o != 0) {
            p = k % o;
          } else {
            p = c - 1;
          }
        }
        break;
      }
    }
    if (ct == 0) cout << id[p - 1] << endl;
  }
}
