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.*;
import java.lang.Math;
public class Main {
	public static void main(String arg[]){
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		int k = sc.nextInt();
		sc.close();
		ArrayList<Long> lista = new ArrayList<Long>();
		long i;
		for(i=1;i<=Math.sqrt(n);i++){	
			if(n%i == 0){
				if(n/i != i) {
					lista.add(n/i);
				}
				lista.add(i);
			}
		}
		Collections.sort(lista);
		if(lista.size() < k){
			System.out.println(-1);
		}else {
			System.out.println(lista.get(k-1));
		}

	}
}