#include <iostream>
#include <string>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include <cmath>
#include <cstdlib>
#include <queue>
#include <stack>
#include <iomanip>

using namespace std;

#define REP(i, n) for(ll i = 0;i < n;i++)
#define REPR(i, n) for(ll i = n;i >= 0;i--)
#define FOR(i, m, n) for(ll i = m;i < n;i++)
#define FORR(i, m, n) for(ll i = m;i >= n;i--)
#define REPO(i, n) for(ll i = 1;i <= n;i++)
#define ll long long
#define INF (ll)1 << 60
#define MINF (-1 * INF)
#define ALL(n) n.begin(),n.end()
#define MOD 1000000007
#define P pair<ll, ll>

ll n, ans = -1;
vector<ll> p, list, able;

bool IsPrime(ll n) {
	if (n <= 1)return false;
	for (ll i = 2; i <= sqrt(n); i++)
	{
		if (n % i == 0)return false;
	}
	return true;
}

vector<ll> era(ll n) {
	vector<bool> ok(n + 1);
	vector<ll> res;
	for (ll i = 2; i <= sqrt(n); ++i) {
		if (IsPrime(i)) {
			for (ll j = i * i; j <= n; j += i) ok[j] = true;
		}
	}
	FOR(i, 2, n + 1)if (!ok[i])res.push_back(i);
	return res;
}

bool check(ll a) {
	while (a > 0) {
		bool ok = false;
		REP(i, able.size()) if (a % 10 == able[i]) ok = true;
		if (!ok)return true;
		a /= 10;
	}
	return false;
}

int main() {
	p = era(5000000);
	cin >> n;
	REP(i, n) {
		ll a;
		cin >> a;
		able.push_back(a);
	}
	list.push_back(-1);
	REP(i, p.size()) {
		if (check(p[i]))list.push_back(i);
	}
	list.push_back(p.size());
	REP(i, list.size() - 1) {
		set<ll> se;
		FOR(j, list[i] + 1, list[i + 1]) {
			ll a = p[j];
			while (a > 0) {
				se.insert(a % 10);
				a /= 10;
			}
		}
		if (se.size() == able.size()) {
			ll l, r;
			if (list[i] == -1)l = 1;
			else l = p[list[i]] + 1;
			if (list[i + 1] == p.size())r = 5000000;
			else r = p[list[i + 1]] - 1;
			ans = max(ans, r - l);
		}
		
	}
	cout << ans << endl;
}