#include <bits/stdc++.h>

#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define RFOR(i, a, b) for (ll i = (b)-1; i >= (a); i--)
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define rep1(i, n) for (ll i = 1; i <= (n); i++)
#define rrep(i, n) for (ll i = (n)-1; i >= 0; i--)

#define pb push_back
#define mp make_pair
#define fst first
#define snd second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define pii pair<int, int>
#define vi vector<int>

using namespace std;
template <class S, class T>
ostream& operator<<(ostream& o, const pair<S, T>& p)
{
    return o << "(" << p.first << "," << p.second << ")";
}
template <class T>
ostream& operator<<(ostream& o, const vector<T>& vc)
{
    o << "sz = " << vc.size() << endl
      << "[";
    for (const T& v : vc)
        o << v << ",";
    o << "]";
    return o;
}
using ll = long long;
constexpr ll MOD = 1000000007;

constexpr ll MAX = 5000000;
bool isprime[MAX + 1];
int digits[MAX + 1][10];
vector<ll> prime;
bool allowed[10];

bool ok(ll interval)
{
    rep1(i, MAX - interval)
    {
        bool flag = true;
        rep(j, 10)
        {
            if (allowed[j]) {
                if (digits[i + interval][j] - digits[i - 1][j] <= 0) {
                    flag = false;
                }
            } else {
                if (digits[i + interval][j] - digits[i - 1][j] > 0) {
                    flag = false;
                }
            }
        }
        if (flag) {
            return true;
        }
    }
    return false;
}

int main()
{
    for (ll i = 2; i <= MAX; i++) {
        isprime[i] = true;
    }

    for (ll i = 2; i <= MAX; i++) {
        if (isprime[i]) {
            for (ll j = 2; i * j <= MAX; j++) {
                isprime[i * j] = false;
            }
        }
    }
    rep(i, 10)
    {
        digits[1][i] = 0;
    }
    for (ll i = 2; i <= MAX; i++) {
        rep(j, 10)
        {
            digits[i][j] = digits[i - 1][j];
        }
        if (isprime[i]) {
            prime.pb(i);
            bool digit[10];
            rep(k, 10)
            {
                digit[k] = false;
            }
            ll p = i;
            while (p > 0) {
                digit[p % 10] = true;
                p /= 10;
            }
            rep(k, 10)
            {
                if (digit[k]) {
                    digits[i][k]++;
                }
            }
        }
    }

    int n;
    cin >> n;
    rep(i, n)
    {
        int a;
        cin >> a;
        allowed[a] = true;
    }

    ll inf = 1;
    ll sup = MAX - 1;
    if (ok(sup)) {
        cout << sup << endl;
        return 0;
    }
    while (inf < sup) {
        const ll mid = (inf + sup) / 2;
        if (ok(mid)) {
            if (inf == mid) {
                break;
            }
            inf = mid;
        } else {
            sup = mid;
        }
    }
    if (ok(inf)) {
        cout << inf << endl;
    } else {
        cout << -1 << endl;
    }

    return 0;
}