import java.util.*;
import java.util.stream.*;
import static java.lang.Math.*;
public class Main{
	public static void main(String... args){
		Scanner sc=new Scanner(System.in);
		int k=sc.nextInt();
		int n=sc.nextInt();
		boolean[] isPrime=new boolean[n+1];
		Arrays.fill(isPrime,true);
		isPrime[0]=false;
		isPrime[1]=false;
		for(int i=2;i<isPrime.length;i++){
			if(!isPrime[i])continue;
			for(int j=2*i;j<isPrime.length;j+=i){
				isPrime[j]=false;
			}
		}
		List<Integer> prime=new ArrayList<>();
		for(int i=0;i<isPrime.length;i++){
			if(isPrime[i])prime.add(i);
		}
		int ok=0;
		while(ok<prime.size()&&prime.get(ok)<k){
			ok++;
		}
		int max=0;
		int maxLength=0;
		for(int i=ok;i<prime.size()-1&&prime.get(i)<=n;i++){
			Set<Integer> set=new HashSet<>();
			int j=i;
			while(j<prime.size()&&(!set.contains(sumNum(prime.get(j))))){
				set.add(sumNum(prime.get(j)));
				//put(set);
				j++;
			}
			if(maxLength<=j-i){
				maxLength=j-i;
				max=prime.get(i);
			}
			
		}
		put(max);
		
		
		
	}
	public static int sumNum(int x){
		int result=0;
		for(char c:Integer.toString(x).toCharArray()){
			result+=c-'0';
		}
		if(result>=10){
			return sumNum(result);
		}else{
			return result;
		}
	}
	public static class Pair{
		final int x,y;
		Pair(int x,int y){
			this.x=x;
			this.y=y;
		}
		@Override
		public String toString(){
			return String.format("Pair(%d,%d)",x,y);
		}
	}
	public static void print(Object object){
        System.out.print(object);
    }
    public static void put(Object object) {
        System.out.println(object);
    }
    public static void put(){
        System.out.println();
    }
 
    public static void print(String format,Object... args){
        System.out.print(String.format(format,args));
    }
    public static void put(String format,Object... args) {
        System.out.println(String.format(format,args));
    }
}