#include <bits/stdc++.h>
const int MYDD = 1e5 + 1103;
int robot[MYDD];
int main() {
  int n, k;
  while (scanf("%d%d", &n, &k) != EOF) {
    for (int j = 1; j <= n; j++) scanf("%d", &robot[j]);
    for (int i = 1; i <= n; i++) {
      if (k - i > 0)
        k = k - i;
      else
        break;
    }
    printf("%d\n", robot[k]);
  }
  return 0;
}
