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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		int k = sc.nextInt();
		
		List<Integer> aList = method1(a);
		List<Integer> bList = method1(b);
		
		List<Integer> ansList = new ArrayList<>();
		
		for (Integer d: aList) {
			for(Integer e: bList) {
				if (d.equals(e)) {
					ansList.add(e);
				}
			}
		}
		System.out.println(ansList.get(ansList.size()-k));
	}
	
	public static List<Integer> method1(int a) {
		List<Integer> list = new ArrayList<>();
		for(int i=1; i<=a; i++) {
			if (a%i==0) {
				list.add(Integer.valueOf(i));
			}
		}
		return list;
	}
}