#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:66777216")
using namespace std;
int main() {
  int n, k, i;
  cin >> n >> k;
  --k;
  for (i = 1; i <= n; ++i) {
    if (k < i) {
      break;
    }
    k -= i;
  }
  int a[300000];
  for (int j = 0; j < n; ++j) {
    cin >> a[j];
  }
  cout << a[k] << endl;
  return 0;
}
