#P762A. k-th divisor

k-th divisor

No submission language available for this problem.

Description

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.

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

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

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

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.

Samples

Sample Input 1

4 2

Sample Output 1

2

Sample Input 2

5 3

Sample Output 2

-1

Sample Input 3

12 5

Sample Output 3

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.