#include <bits/stdc++.h>
  
using namespace std;
  
#define rep(i,n) REP(i,0,n)
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for(int i=(int)(s-1); i>=(int)(e); i--)
#define pb push_back
#define all(r) r.begin(),r.end()
#define rall(r) r.rbegin(),r.rend()
#define fi first
#define se second
  
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
const int INF = 1e9;
const ll MOD = 1e9 + 7;
double EPS = 1e-8;

using u32 = unsigned int;
using u64 = unsigned long long;
using u128 = __uint128_t;

template <class Uint, class BinOp>
bool is_prime_impl(const Uint &n, const Uint *witness, BinOp modmul) {
    if (n == 2) return true;
    if (n < 2 || n % 2 == 0) return false;
    const Uint m = n - 1, d = m / (m & -m);
    auto modpow = [&](Uint a, Uint b) {
        Uint res = 1;
        for (; b; b /= 2) {
            if (b & 1) res = modmul(res, a);
            a = modmul(a, a);
        }
        return res;
    };
    auto suspect = [&](Uint a, Uint t) {
        a = modpow(a, t);
        while (t != n - 1 && a != 1 && a != n - 1) {
            a = modmul(a, a);
            t = modmul(t, 2);
        }
        return a == n - 1 || t % 2 == 1;
    };
    for (const Uint *w = witness; *w; w++) {
        if (*w % n != 0 && !suspect(*w, d)) return false;
    }
    return true;
}

bool is_prime(const u128 &n) {
    assert(n < 1ULL << 63);
    if (n < 1ULL << 32) {
        // n < 2^32
        constexpr u64 witness[] = {2, 7, 61, 0};
        auto modmul = [&](u64 a, u64 b) { return a * b % n; };
        return is_prime_impl<u64>(n, witness, modmul);
    } else {
        // n < 2^63
        constexpr u128 witness[] = {2, 325, 9375, 28178, 450775, 9780504, 1795265022, 0};
        // if u128 is available
        auto modmul = [&](u128 a, u128 b) { return a * b % n; };
        // otherwise
        // auto modmul = [&](u64 a, u64 b) {
        //     u64 res = 0;
        //     for (; b; b /= 2) {
        //         if (b & 1) res = (res + a) % n;
        //         a = (a + a) % n;
        //     }
        //     return res;
        // };
        return is_prime_impl<u128>(n, witness, modmul);
    }
}

int main(){
    int n;
    cin >> n;
    vl a(n);
    rep(i, n) cin >> a[i];
    ll ans = -1LL;
    do {
        ll tmp = 0LL;
        rep(i, n) {
            if(a[i] > 9) tmp *= 100;
            else tmp *= 10;
            tmp += a[i];
        }
        if(is_prime(tmp)) ans = max(ans, tmp);
    }while(next_permutation(all(a)));
    cout << ans << endl;
    return 0;
}