#include <bits/stdc++.h>
using namespace std;
const long long maxN = 1e6 + 5;
const long long inf = 1e10;
const long long mod = 1e9 + 7;
long long n, k;
long long a[maxN];
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n >> k;
  for (long long i = 1; i <= n; i++) cin >> a[i];
  long long res = 1;
  for (long long i = 1; i <= maxN; i++) {
    long long tmp = (i * (i + 1)) / 2;
    if (k <= tmp) {
      res = i;
      break;
    }
  }
  k -= (res * (res - 1)) / 2;
  cout << a[k];
  return 0;
}
