Problem: You are given two integers n and k. Find k-th smallest divisor of n, or report that it doesn't exist.

Divisor of n is any such natural number, that n can be divided by it without remainder.

Input

The first line contains two integers n and k (1 ≤ n ≤ 1015, 1 ≤ k ≤ 109).

Output

If n has less than k divisors, output -1.

Otherwise, output the k-th smallest divisor of n.

Examples

Input

4 2


Output

2


Input

5 3


Output

-1


Input

12 5


Output

6

Note

In the first example, number 4 has three divisors: 1, 2 and 4. The second one is 2.

In the second example, number 5 has only two divisors: 1 and 5. The third divisor doesn't exist, so the answer is -1.

Solution (in JAVA):

Solution:
import java.util.*;
public class Main{
  public static void main(String args[]){
    Scanner s=new Scanner (System.in);  
    long n=s.nextLong();
    int q=s.nextInt();
    ArrayList < Long > al = new ArrayList < Long > ();
    
    for (long i = 1; i <= Math.sqrt(n); i++) {
      
      if (n % i == 0) {
        
        if (n / i == i) {
          al.add(i );
        } else {
          al.add(i);
          al.add(n/i);
        }
      }
    }
    Collections.sort(al); 
    //System.out.println(al);
    if(al.size()>=q){
      System.out.println(al.get(q-1));
    }else{
    System.out.println("-1");
    }
  }
}