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-----
8 12 2

-----Sample Output-----
2

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

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