#include <bits/stdc++.h>
using namespace std;
template <typename P, typename Q>
ostream& operator<<(ostream& os, pair<P, Q> p) {
  os << "(" << p.first << "," << p.second << ")";
  return os;
}
int main(int argc, char* argv[]) {
  int n, k;
  while (scanf("%d%d", &n, &k) == 2) {
    vector<int> v;
    for (int i = 0; i < n; ++i) {
      int m;
      scanf("%d", &m);
      v.push_back(m);
    }
    long long int sum = 0;
    for (int i = 0; i < n; ++i) {
      long long int s = sum + i + 1;
      if (k <= s) {
        printf("%d\n", v[k - sum - 1]);
        break;
      }
      sum = s;
    }
  }
  return 0;
}
