import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int k = sc.nextInt();
        HashMap<Integer, Integer> map = new HashMap<>();
        int x = n;
        for (int i = 2; i <= Math.sqrt(x); i++) {
            while (x % i == 0) {
                if (map.containsKey(i)) {
                    map.put(i, map.get(i) + 1);
                } else {
                    map.put(i, 1);
                }
                x /= i;
            }
        }
        if (x > 1) {
            if (map.containsKey(x)) {
                map.put(x, map.get(x) + 1);
            } else {
                map.put(x, 1);
            }
        }
        int max = 0;
        int maxNumber = 0;
        for (int i = 2; i < n; i++) {
            int y = i;
            int count = 0;
            for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
                for (int j = 0; j < entry.getValue() && count < k; j++) {
                    if (y % entry.getKey() == 0) {
                        y /= entry.getKey();
                        count++;
                    } else {
                        break;
                    }
                }
                if (count >= k) {
                    break;
                }
            }
            if (count >= k) {
                int m = getCount(i);
                if (max < m) {
                    max = m;
                    maxNumber = i;
                }
            }
        }
        System.out.println(maxNumber);
    }
    
    static int getCount(int x) {
        int count = 1;
        for (int i = 2; i <= Math.sqrt(x); i++) {
            if (x % i == 0) {
                int cnt = 0;
                while(x % i == 0) {
                    cnt++;
                    x /= i;
                }
                count *= (cnt + 1);
            } 
        }
        if (x > 1) {
            count *= 2;
        }
        return count;
    }

}