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 Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)

import static java.lang.System.*;
import java.util.*;

public class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Scanner sc = new Scanner(in);

		int a = sc.nextInt();
		int b = sc.nextInt();
		int k = sc.nextInt();
		
		int count = 0;
		for(int i=Math.min(a, b); i>0; i--) {
			if(a%i==0 && b%i==0) count++;
			if(count==k) {
				out.println(i);
				break;
			}
		}
	}

}