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 sys
import math
n, k = map(int, input().split())
if(n < k):
    print(-1)
    sys.exit(0)
i = 1
fdivs = []
ldivs = []
while(i <= math.sqrt(n)):
    if(n % i == 0):
        fdivs.append(i)
        if(i != (n // i)):
            ldivs.append(n // i)
    i+=1
ldivs.reverse()
divs = fdivs + ldivs
try:
    print(divs[k-1])
except:
    print(-1)