#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

int myhash(int x) {
	if (x < 10) return x;
	int sum = 0;
	while (x) {
		sum += x % 10;
		x /= 10;
	}
	return myhash(sum);
}

int main() {
	int K, N; cin >> K >> N;
	vector<bool> prime(N + 1, true);
	prime[0] = prime[1] = false;
	for (int i = 2; i <= N; i++)
		if (prime[i])
			for (int j = i * 2; j <= N; j += i)
				prime[j] = false;
	vector<int> p;
	for (int i = 0; i <= N; i++)
		if (prime[i])
			p.push_back(i);
	int n = p.size();
	i_i ans(0, 0);
	int k = lower_bound(p.begin(), p.end(), K) - p.begin();
	for (; k < n; k++) {
		vector<bool> a(10);
		int l;
		for (l = k; l < n; l++) {
			int x = myhash(p[l]);
			if (a[x]) break;
			a[x] = true;
		}
		ans = max(ans, i_i(l - k, k));
	}
	cout << p[ans.second] << endl;
}