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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
class Program{
	public static void Main(string[] args){
    	string[] input = Console.ReadLine().Split(' ');
      	int A = int.Parse(input[0]);
      	int B = int.Parse(input[1]);
        int K = int.Parse(input[2]);
      
      	List<int> list = new List<int>();
      	for(int i = 1;i <= Math.Min(A,B);i++){
        	if(A%i == 0&&B%i ==0){
            	list.Add(i);
            }
        }
      
      	Console.WriteLine(list[list.Count - K]);
      	//Console.WriteLine(list.Count);
    }
}