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: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ABC_120
{
    class B
    {
        static bool IsDivide(int x, int y)
        {
            while (y % 2 == 0) y /= 2;
            while (y % 5 == 0) y /= 5;
            if (x % y == 0) return true;
            else return false;
        }

        static void Main(string[] args)
        {
            int[] n = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            int a = n[0], b = n[1], K = n[2];

            int counter = 0;
            int index = 0;
            for(int i = 1; i < 100; i++)
            {
                
                if (IsDivide(a,i) && IsDivide(b,i)) counter++;

                if (counter >= K)
                {
                    index = i;
                    break;
                }
            }

            Console.WriteLine(index);
        }


    }
}