#include<bits/stdc++.h>
typedef long long ll;
using namespace std;
int INF = 1e9;
int MOD = 1e9+7;
bool prime[200001];
int root[200001];
main(){
    for(int i = 2;i*i <= 200000;i++){
        if(prime[i])continue;
        for(int j = i*2;j <= 200000;j+=i)prime[j] = 1;
    }
    for(int i = 1;i <= 200000;i++){
        if(prime[i])root[i] = -1;
        else root[i] = i % 9;
    }
    int K,N,maxi = 1,maxn;
    cin >> K >> N;
    for(int i = max(2,K);i <= N;i++){
        if(prime[i])continue;
        int cnt = 1;
        bool used[10] = {};
        used[root[i]] = 1;
        for(int j = i+1;j <= N;j++){
            if(prime[j])continue;
            if(used[root[j]])break;
            else{
                used[root[j]] = 1;
                cnt++;
            }
        }
        if(maxi <= cnt){
            maxi = cnt;
            maxn = i;
        }
    }
    cout << maxn << endl;
}