import java.math.BigInteger;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Scanner;
import java.util.stream.IntStream;

public class Main {
    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int n = stdin.nextInt();
        String[] a = new String[n];
        IntStream.range(0, n).forEach(i -> a[i] = stdin.next());
        
        Deque<String> strs = new ArrayDeque<>();
        Deque<Integer> bits = new ArrayDeque<>();
        
        strs.addLast("");
        bits.addLast(0);
        
        BigInteger answer = new BigInteger("-1");
        while (!strs.isEmpty()) {
            String str = strs.pollFirst();
            int bit = bits.pollFirst();
            
            if (bit == (1 << n) - 1) {
                BigInteger val = new BigInteger(str);
                if (val.isProbablePrime(1)) answer = answer.max(val);
            } else {
                for (int i = 0; i < n; i++) {
                    if ((bit & (1 << i)) != 0) continue;
                    
                    strs.addLast(str + a[i]);
                    bits.addLast(bit | (1 << i));
                }  
            }
        }
        
        System.out.println(answer);
    }
}