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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"fmt"
)

func main() {
	var a, b, k int
	_, _ = fmt.Scan(&a, &b, &k)
	max := a
	if max < b {
		max = b
	}
	count := 0
	ans := 0
	for i := max; max > 0; i-- {
		if count >= k {
			break
		}
		if a % i == 0 && b % i == 0 {
			count++
			ans = i
		}
	}
	fmt.Println(ans)
}