A. k-th divisortime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou 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.InputThe first line contains two integers n and k (1 ≤ n ≤ 1015, 1 ≤ k ≤ 109).OutputIf n has less than k divisors, output -1.Otherwise, output the k-th smallest divisor of n.ExamplesInput4 2Output2Input5 3Output-1Input12 5Output6NoteIn 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.
Input4 2
Output2
['math', 'number theory', '*1400']