// includes #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // macros #define ll long long int #define pb emplace_back #define mk make_pair #define pq priority_queue #define FOR(i, a, b) for(int i=(a);i<(b);++i) #define rep(i, n) FOR(i, 0, n) #define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--) #define all(x) (x).begin(),(x).end() #define sz(x) ((int)(x).size()) #define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end()) using namespace std; // types typedef pair P; typedef pair Pl; typedef pair Pll; typedef pair Pd; // constants const int inf = 1e9; const ll linf = 1LL << 50; const double EPS = 1e-10; const int mod = 1e9 + 7; // solve template bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;} template bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;} template vector list_prime(T n){ vector res; vector i_prime = vector(n+1, true); for(ll i = 2; i <= n; i++){ if(i_prime[i]){ res.push_back(i); for(ll j = 2; j * i <= n; j++){ i_prime[i * j] = false; } } } return res; } int main(int argc, char const* argv[]) { ios_base::sync_with_stdio(false); cin.tie(0); int n; cin >> n; vector a(n); vector b(10, false); rep(i, n){ cin >> a[i]; b[a[i]] = true; } auto p = list_prime(5000000); vector v; for(int i = 0; i < sz(p); i++){ int tmp = p[i]; while(tmp){ if(!b[tmp % 10]){ v.pb(i); break; } tmp /= 10; } } if(sz(v) == 0){ cout << 4999999 << endl; return 0; } int res = -1; for(int i = 0; i < sz(v) - 1; i++){ vector used(10, false); bool flag = false; for(int j = v[i]+1; j < v[i+1]; j++){ flag = true; int tmp = p[j]; while(tmp){ used[tmp % 10] = true; tmp /= 10; } } for(int j = 0; j < n; j++)flag = flag & (used[a[j]]); if(flag)res = max(res, p[v[i+1]] - p[v[i]] - 2); } vector used(10, false); bool flag = false; for(int i = 0; i < v[0]; i++){ flag = true; int tmp = p[i]; while(tmp){ used[tmp % 10] = true; tmp /= 10; } } for(int i = 0; i < 10; i++){ flag = flag & ((b[i] && used[i]) || (!b[i] && !used[i])); } if(flag)res = max(res, p[v[0]]); used.assign(10, false); flag = false; for(int i = v[sz(v)-1] + 1; i < sz(p); i++){ flag = true; int tmp = p[i]; while(tmp){ used[tmp % 10] = true; tmp /= 10; } } for(int i = 0; i < 10; i++){ flag = flag & ((b[i] && used[i]) || (!b[i] && !used[i])); } if(flag)res = max(res, 5000000 - p[v[sz(v)-1]]); cout << res << endl; return 0; }