Problem:
Score : 200 points

Problem Statement

You are given positive integers A and B.

Find the K-th largest positive integer that divides both A and B.

The input guarantees that there exists such a number.

Constraints

All values in input are integers.

1 \leq A, B \leq 100

The K-th largest positive integer that divides both A and B exists.

K \geq 1

Input

Input is given from Standard Input in the following format:

A B K

Output

Print the K-th largest positive integer that divides both A and B.

Sample Input 1

8 12 2

Sample Output 1

2

Three positive integers divides both 8 and 12: 1, 2 and 4.
Among them, the second largest is 2.

Sample Input 2

100 50 4

Sample Output 2

5

Sample Input 3

1 1 1

Sample Output 3

1

Solution in Python (3.4.3) (judge verdict: Accepted)

a,b,c = map(int, input().split())
def m(num):
    if num < 1:
        return []
    elif num == 1:
        return [1]
    else:
        divisor_list = []
        divisor_list.append(1)
        for i in range(2, num // 2 + 1):
            if num % i == 0:
                divisor_list.append(i)
        divisor_list.append(num)

        return divisor_list


list = m(a)+ m(b)
res = [e for e in set(list) if list.count(e) > 1]
res.sort(reverse=True)
print(res[c-1])