#include using namespace std; template T gcd(T a, T b) { while (b) { T tmp = b; b = a % b; a = tmp; } return a; } template T pow_mod(T a, T n, T mod) { T r = 1; for (; n; n >>= 1) { if (n & 1) { (r *= a) %= mod; } (a *= a) %= mod; } return r; } template bool miller_rabin(T n) { if (n < 2) { return false; } for (T a = 2; a < min(T(30), n); a++) { if (gcd(a, n) != 1) { continue; } T m = n - 1; if (pow_mod(a, m, n) != 1) { return false; } for (m >>= 1; m % 2 == 0; m >>= 1) { T puni = pow_mod(a, m, n); if (puni == n - 1) { break; } if (puni != 1) { return false; } } T puni = pow_mod(a, m, n); if ((puni != n - 1) && (puni != 1)) { return false; } } return true; } int main() { auto is_prime = [](__int128_t n) { return miller_rabin(n); }; int n; cin >> n; vector as(n); for (auto &a : as) { cin >> a; } int64_t ans = -1; do { string s = ""s; for (auto &a : as) { s += to_string(a); } __int128_t x = stoll(s); if (is_prime(x)) { ans = max(ans, int64_t(x)); } } while (next_permutation(as.begin(), as.end())); cout << ans << endl; return 0; }