#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#include <boost/multiprecision/cpp_int.hpp>
namespace mp = boost::multiprecision;
using u128 = mp::cpp_int;
#else
#define dump(...)
using u128 = __uint128_t;
#endif

//#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = 1'000'000'007;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }

template<typename T>
T modpow(T a, T e, T mod) {
	T res = 1;
	while (e > 0) {
		if (e & 1)res = res * a % mod; // modmul(res, a, mod);
		a = a * a % mod; // modmul(a, a, mod);
		e >>= 1;
	}
	return res;
}

template<typename T>
bool millerRabinPrimalityTest(T n, int iteration = 5) {
	if (n < 2)return false;
	if (n == 2)return true;
	if (n % 2 == 0)return false;
	T d = n - 1;
	while (d % 2 == 0)d /= 2;
	for (int i = 0; i < iteration; i++) {
		T a = rand() % (n - 1) + 1, t = d;
		T mod = modpow(a, t, n);
		while (t != n - 1 && mod != 1 && mod != n - 1) {
			mod = mod * mod % n; //modmul(mod, mod, n);
			t *= 2;
		}
		if (mod != n - 1 && t % 2 == 0)return false;
	}
	return true;
}

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n; cin >> n;
	vector<int> a(n); rep(i, 0, n) {
		cin >> a[i];
	}
	sort(all(a));
	long long ans = -1;
	do {
		long long x = 0;
		rep(i, 0, n) {
			if (a[i] >= 10) {
				x *= 100;
				x += a[i];
			}
			else {
				x *= 10;
				x += a[i];
			}
		}
		if (millerRabinPrimalityTest(u128(x)))
			chmax(ans, x);
	} while (next_permutation(all(a)));
	cout << ans << endl;
	return 0;
}