//#include <tourist>
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> p;
const int INF = 1e9;
const ll LINF = ll(1e18);
const int MOD = 1000000007;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {-1, 0, 1, 0};
const int Dx[8] = {0, 1, 1, 1, 0, -1, -1, -1}, Dy[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
#define yes cout << "Yes" << endl
#define YES cout << "YES" << endl
#define no cout << "No" << endl
#define NO cout << "NO" << endl
#define rep(i, n) for (int i = 0; i < n; i++)
#define ALL(v) v.begin(), v.end()
#define debug(v)          \
    cout << #v << ":";    \
    for (auto x : v)      \
    {                     \
        cout << x << ' '; \
    }                     \
    cout << endl;
template <class T>
bool chmax(T &a, const T &b)
{
    if (a < b)
    {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
bool chmin(T &a, const T &b)
{
    if (b < a)
    {
        a = b;
        return 1;
    }
    return 0;
}
//cout<<fixed<<setprecision(15);有効数字15桁
//-std=c++14
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
ll n, k;
//エラトステネスの篩
vector<bool> sieve(int n)
{
    vector<bool> isp(n + 1, true);
    isp[0] = false;
    isp[1] = false;
    for (int i = 2; pow(i, 2) <= n; i++)
    {
        if (isp[i])
            for (int j = 2; i * j <= n; j++)
            {
                isp[i * j] = false;
            }
    }
    return isp;
}
int calc(int h)
{
    while (h >= 10)
    {
        int t = 0;
        while (h)
        {
            t += h % 10;
            h /= 10;
        }
        h = t;
    }
    return h;
}
int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> k >> n;
    vector<bool> isp = sieve(n);
    vector<int> sosuu;
    vector<int> sosuu_c;
    rep(i, isp.size())
    {
        if (isp[i])
            sosuu.push_back(i);
    }
    rep(i, sosuu.size())
    {
        sosuu_c.push_back(calc(sosuu[i]));
    }
    int ans = 0;
    int size = 0;
    rep(i, sosuu.size())
    {
        if (sosuu[i] < k)
            continue;
        vector<bool> flag(10);
        int size_t = 0;
        rep(j, 10)
        {
            if (i + j == sosuu.size())
                break;
            if (flag[sosuu_c[i + j]])
                break;
            flag[sosuu_c[i + j]] = true;
            size_t++;
        }
        if (size <= size_t)
        {
            ans = sosuu[i];
            size = size_t;
        }
    }
    cout << ans << "\n";
}