package no006;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int n = sc.nextInt();
		ArrayList<Integer> primes = Sieve.primeList(n);
		int ans = 0;
		int max = 0;
		int i = 0;
		while(i < primes.size() && primes.get(i) < k) {
			i++;
		}
		for(;i<=n;i++) {
			boolean[] used = new boolean[10];
			for(int j=i;j<primes.size();j++) {
				int h = uselessHash(primes.get(j));
				if (used[h]) {
					break;
				}
				used[h] = true;
				if (j-i+1 >= max) {
					max = j - i + 1;
					ans = primes.get(i);
				}
			}
		}
		System.out.println(ans);
	}

	static int uselessHash(int n) {
		while(n >= 10) {
			int sum = 0;
			while(n > 0) {
				sum += n % 10;
				n /= 10;
			}
			n = sum;
		}
		return n;
	}

}
class Sieve {
	public static boolean[] isPrimeArray(int max) {
		boolean[] isPrime = new boolean[max+1];
		Arrays.fill(isPrime, true);
		isPrime[0] = isPrime[1] = false;
		for(int i=2;i*i<=max;i++) {
			if (isPrime[i]) {
				int j = i * 2;
				while(j<=max) {
					isPrime[j] = false;
					j += i;
				}
			}
		}
		return isPrime;
	}
	public static ArrayList<Integer> primeList(int max) {
		boolean[] isPrime = isPrimeArray(max);
		ArrayList<Integer> primeList = new ArrayList<>();
		for(int i=2;i<=max;i++) {
			if (isPrime[i]) {
				primeList.add(i);
			}
		}
		return primeList;
	}
}