#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, k;
  cin >> n >> k;
  long long arr[n];
  for (long long int i = 0; i < n; i++) {
    cin >> arr[i];
  }
  long long ans, d;
  for (long long int i = 1; i <= n; i++) {
    long long diff = k - (i * (i + 1)) / 2;
    if (diff <= 0) {
      ans = i - 1;
      d = k - (ans * (ans + 1)) / 2;
      break;
    }
  }
  if (d == 0) {
    cout << arr[ans - 1];
  } else {
    cout << arr[d - 1];
  }
  return 0;
}
