백준 #2501번 약수 구하기

import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int k = sc.nextInt();
		int count = 0;
		int i;
		
		for(i = 1; i <= n; i++) {
			if(n % i == 0) {
				count++;
			}
			
			if(count == k)
				break;
		}
		
		if(count < k) {
			System.out.println("0");
		}else {
			System.out.println(i);
		}
		sc.close();
	}
}