#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 5e6+1;
bool isp[N];
void init(){
    isp[2]=true;
    for(int i=3;i<N;i+=2) isp[i]=true;
    for(ll i=3;i<N;i+=2){
        if(i*i>=N) break;
        if(!isp[i]) continue;
        for(auto j=i*i; j<N;j+=i+i) isp[j]=false;
    }

}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    init();
    auto num_to_set = [&] (ll x){
        ll ret = 0;
        while(x){
            ret |= 1<<(x%10);
            x/=10;
        }
        return ret;
    };

    int N; cin>>N;
    ll full=0;
    for(int i=0;i<N;++i){
        ll x;cin>>x;
        full|=1<<x;
    }

    using P = pair<ll, ll>;
    vector<P> ok;
    vector<ll> ng;
    for(int i=2;i<::N;++i){
        if(!isp[i]) continue;
        auto se = num_to_set(i);
        if(se & (~full)) ng.emplace_back(i);
        else ok.emplace_back(i, se);
    }

    ng.emplace_back(::N);
    ok.emplace_back(::N, 0);
    ll L=1,i=0;
    ll ans=-1;
    for(auto&x:ng){
        ll R=x-1;
        ll se=0;
        while(true){
            auto [p, s] = ok[i];
            if(p>R) break;
            se|=s;
            i+=1;
        }
        if(se==full&&ans<R-L) ans=R-L;
        L=x+1;
    }
    cout<<ans<<endl;
    return 0;
}