#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

int N;
int A[10];
ll ret=-1;

bool isprime(ll v) {
	for(ll i=2;i*i<=v;i++) if(v%i==0) return false;
	return (v!=1);
}

void dfs(ll cur,int mask) {
	if(cur>ret && isprime(cur)) ret=cur;
	
	int i;
	FOR(i,N) if((mask&(1<<i))==0) {
		ll ne;
		if(A[i]>=10) ne=cur*100+A[i];
		else ne=cur*10+A[i];
		dfs(ne,mask|(1<<i));
	}
	
}


void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	FOR(i,N) cin>>A[i];
	
	int ma=-1;
	dfs(0,0);
	
	cout<<ret<<endl;
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}