#include <bits/stdc++.h>
using namespace std;
const int maxN = 100000 + 10;
int id[maxN + 10];
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 1; i <= n; ++i) cin >> id[i];
  for (int i = 1; i <= n; ++i)
    if (k <= i) {
      cout << id[k] << endl;
      return 0;
    } else
      k -= i;
  return 0;
}
