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 PYTHON3):

Solution:
### PREYANSH RASTOGI
### 2017176

import math


if __name__ == '__main__':
	
	n, k  = [int(x) for x in input().split()]
	arr = []
	for i in range(1,int(math.sqrt(n))+1) :
		if n%i == 0  :
			if i**2!=n :
				arr.append(i)
				arr.append(n//i)
			else :
				arr.append(i)
	arr.sort()
	try :
		print(arr[k-1])
	except IndexError :
		print(-1)