#include<bits/stdc++.h>
using namespace std;

//#define int long long

typedef long long ll;
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define ln <<endl
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
template<class T,class U>void chmin(T &t,U f){if(t>f)t=f;}
template<class T,class U>void chmax(T &t,U f){if(t<f)t=f;}

vint p;
bool f[5000000];

bool ex[400000][10];
int N;
int ok[10],cnt[10];

bool check(){
    rep(i,10)if(!ok[i]&&cnt[i])return false;
    return true;
}

signed main(){
    fill_n(f,5000000,1);
    f[0]=f[1]=0;
    p.pb(0);
    for(int i=2;i<5000000;i++){
        if(!f[i])continue;
        p.pb(i);
        for(int j=2;i*j<5000000;j++)f[i*j]=0;
    }
    p.pb(5000001);

    reps(i,1,p.size()-1){
        string s;
        stringstream ss;ss<<p[i];ss>>s;
        rep(j,s.size())ex[i][s[j]-'0']=1;
    }


    cin>>N;
    rep(i,N){
        int a;cin>>a;ok[a]=1;
    }
    int l=1;
    int ans=-1;
    reps(i,1,p.size()-1){
        rep(j,10)cnt[j]+=ex[i][j];
        while(l<=i&&!check()){
            rep(j,10)cnt[j]-=ex[l][j];
            l++;
        }
        bool y=true;
        rep(j,10)y&=!((cnt[j]!=0)^ok[j]);
        if(y){
            int hoge=p[l-1]+1;
            int piyo=p[i+1]-1;
            chmax(ans,piyo-hoge);
        }
    }

    cout<<ans<<endl;
    return 0;
}