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.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Eric
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BKThCommonDivisor solver = new BKThCommonDivisor();
        solver.solve(1, in, out);
        out.close();
    }

    static class BKThCommonDivisor {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int A = in.nextInt();
            int B = in.nextInt();
            int K = in.nextInt();
            int res = solve(A, B, K);
            out.println(res);
        }

        private int solve(int a, int b, int K) {
            int cur = 0;
            for (int i = 101; i >= 1; i--) {
                if (a % i == 0 && b % i == 0) {
                    cur++;
                    if (cur == K)
                        return i;
                }
            }
            throw new RuntimeException("Impossible");
        }

    }
}