#include <bits/stdc++.h>
#pragma warning(disable : 4996)
int main() {
  int n, k;
  scanf("%d %d", &n, &k);
  std::vector<int> vec(n);
  for (int i = 0; i < n; ++i) scanf("%d", &vec[i]);
  for (int i = 0; i < n; ++i) {
    if (k <= i + 1) {
      break;
    } else {
      k -= i + 1;
    }
  }
  printf("%d", vec[k - 1]);
}
