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> inner = new HashMap<>();
        int x = n;
        for (int i = 2; i <= Math.sqrt(n); i++) {
            while (x % i == 0) {
                inner.put(i, inner.getOrDefault(i, 0) + 1);
                x /= i;
            }
        }
        if (x > 1) {
            inner.put(x, inner.getOrDefault(x, 0) + 1);
        }
        int[] totals = new int[n];
        int max = 0;
        int ans = 0;
        for (int i = 2; i < n; i++) {
            boolean flag = (totals[i] == 0);
            for (int j = 1; j * i < n; j++) {
                totals[i * j]++;
            }
            if (max < totals[i]) {
                if (getCount(i, inner) >= k) {
                    max = totals[i];
                    ans = i;
                }
            }
        }
        System.out.println(ans);
    }
    
    static int getCount(int x, HashMap<Integer, Integer> inner) {
        int count = 0;
        for (int y : inner.keySet()) {
            for (int i = 0; i < inner.get(y); i++) {
                if (x % y == 0) {
                    count++;
                    x /= y;
                } else {
                    break;
                }
            }
        }
        return count;
    }
}