#include <stdio.h>
#include <algorithm>
#include <set>
using namespace std;

bool isp(long long x)
{
	if (x == 1) return false;
	for (long long i=2;i*i<=x;i++) if (x % i == 0) return false;
	return true;
}

int main()
{
	int N; scanf ("%d",&N);
	int A[10]; for (int i=0;i<N;i++) scanf ("%d",&A[i]);

	long long ans = -1;
	set<long long> chk;
	do{
		long long a = 0;
		for (int i=0;i<N;i++){
			if (A[i] < 10) a = a * 10 + A[i];
			else a = a * 100 + A[i];
		}
		if (chk.count(a)) continue;
		else{
			chk.insert(a);
			if (isp(a)) ans = max(ans,a);
		}
	}while(next_permutation(A,A+N));

	printf ("%lld\n",ans);
	return 0;
}