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
n,k=map(int,raw_input().split())
l=[]

for j in range(1,(int(math.sqrt(n))+1)):
    if n%j==0:
        ll = len(l) / 2
        l.insert(ll,j)
        if n//j !=j:
            ll = len(l) / 2
            l.insert(ll+1,n//j)

print l[k-1] if len(l)>=k else -1