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 PYTHON):

Solution:
import math

inp=list(map(int,raw_input().split()))

n=inp[0]
k=inp[1]

i=1
l=[]

while(i<=math.sqrt(n)):
	
	if(n%i==0):
		l.append(i)
		if(int(n//i)!=l[-1]):
			l.append(int(n//i))
		
	i=i+1

if(k>len(l)):
	print(-1)
else:
	l.sort()
	print(l[k-1])