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:
import math
a=input()
b=a.split()
n=int(b[0])
k=int(b[1])
b=int(math.sqrt(n))
l=[]
for i in range(1,b+1):
    if n%i==0:
        l.append(i)
        if i!=n//i:
            l.append(n//i)
        
l.sort()
m=len(l)

if k<=m:
    print(l[k-1])
else:
    print(-1)