#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, k;
  cin >> n >> k;
  long long int a[n + 10];
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  long long int cnt = 1, temp, sum = 0;
  while (1) {
    temp = sum;
    if (cnt % 2 == 0) {
      sum = (cnt / 2) * (cnt + 1);
    } else {
      sum = ((cnt + 1) / 2) * cnt;
    }
    if (sum == k) {
      cout << a[cnt] << endl;
      return 0;
    } else if (sum > k) {
      long long int res = k - temp;
      cout << a[res] << endl;
      return 0;
    }
    cnt++;
  }
  return 0;
}
