#include <bits/stdc++.h>
using namespace std;
long long a[100005];
int main() {
  long long n, k, tmp;
  cin >> n >> k;
  for (long long i = 1; i < n + 1; i++) cin >> a[i];
  long long cur = 1;
  while (1) {
    if (k - cur <= 0)
      break;
    else {
      k -= cur;
      cur++;
    }
  }
  cout << a[k];
  return 0;
}
