#include <iostream>
#include <vector>

int main() {
    using namespace std;
    int k, n;
    cin >> k >> n;

    vector<bool> is_prime(n + 1, true);
    for (int i = 2; i <= n / i; i++) {
        if (!is_prime[i]) { continue; }
        for (int j = i * i; j <= n; j += i) { is_prime[j] = false; }
    }
    vector<int> primes;
    for (int i = 2; i <= n; i++) {
        if (i >= k && is_prime[i]) { primes.push_back(i); }
    }

    constexpr int MOD = 9;
    const int m = primes.size();
    int ans = 0, max_size = 0, cnt = 0, r = 0;
    vector<bool> used(MOD, false);
    for (int l = 0; l < m; l++) {
        while (r < m && cnt < MOD) {
            if (used[primes[r] % MOD]) { break; }
            used[primes[r] % MOD] = true;
            cnt++;
            r++;
        }
        if (r - l >= max_size) {
            ans = primes[l];
            max_size = r - l;
        }
        used[primes[l] % MOD] = false;
        cnt--;
    }
    cout << ans << endl;
}