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 ≤ 10^15, 1 ≤ k ≤ 10^9).

-----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.