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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;

int a, b, k;

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cin >> a >> b >> k;
	int c = 0;
	for(int i=min(a, b); i>=1; --i){
		if(a % i == 0 && b % i == 0){
			++c;
//			cout << i << " " << c << "\n";
			if(c == k){
				cout << i << "\n";
				return 0;
			}
		}
	}
}