// what is matter? never mind. 
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,sse4,popcnt,abm,mmx,avx,avx2") 
#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rep(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
#define ull unsigned long long
//#define int long long
using namespace std;
inline int read()
{
    char c=getchar();int x=0;bool f=0;
    for(;!isdigit(c);c=getchar())f^=!(c^45);
    for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
    if(f)x=-x;return x;
}

#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int,int>pii;
typedef vector<int>vi;
 
#define maxn 3000005
#define inf 0x3f3f3f3f

int pri[maxn],phi[maxn],tot;
int mu[maxn],smu[maxn],sphi[maxn];
bool vis[maxn];

int res[1066];

void prework(int n)
{
	vis[1]=1,mu[1]=1,phi[1]=1;
	For(i,2,n)
	{
		if(!vis[i]){
			pri[++tot]=i;
			int s=0;
			int j=i;
			while(j)s|=(1<<(j%10)),j/=10;
			
			bool in=0;
			For(t,0,1023) if(!res[t] && !((t&s))) {
				res[t]=i; in=1;
			}
	//		if(in) cerr<<"i: "<<i<<"\n";
		}
		For(j,1,tot)
		{
			if(i*pri[j]>n)break;
			vis[i*pri[j]]=1;
			if(i%pri[j]){
				
			}else{
				break;
			}
		}
	}
}

signed main()
{
	prework(2e6);
	int n=read(),s=0;
	For(i,1,n){
		int x=read();
		s|=(1<<x);
	}
	if(res[s]==0)res[s]=-1;
	cout<<res[s];
    return 0;
}
/*
5 10 5
01234
0 1

01234

*/