#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>

using namespace std;

vector<bool> prime;
vector<int> p;

//O(NloglogN)
void erat(long long N){
    prime.resize(N+1, 1);
    prime[0] = 0;
    prime[1] = 0;
    for (long long i=2; i*i<=N; i++){
        if (prime[i]){
            for (long long j=i*2; j <= N; j+=i){
                prime[j] = 0;
            }
        }
    }
}

map<int, int> mp;
set<int> st;

void update(int X, int p){
    set<int> st2;
    while(X != 0){
        st2.insert(X%10);
        X /= 10;
    }
    for (auto x : st2){
        if (p == 1) mp[x]++;
        else mp[x]--;
    }
}

bool check1(){
    for (int i=0; i<=9; i++){
        if (!st.count(i) && mp[i] > 0) return 0;
    }
    return 1;
}

bool check2(){
    for (int i=0; i<=9; i++){
        if (!st.count(i) && mp[i] > 0 || (st.count(i) && mp[i] == 0)) return 0;
    }   
    return 1;
}

int main(){

    int N, M, A, l=0, a, b, ans=-1;
    cin >> N;
    erat(5000000);
    for (int i=1; i<=5000000; i++){
        if (prime[i]) p.push_back(i);

    }
    for (int i=0; i<N; i++){
        cin >> A;
        st.insert(A);
    }
    M = p.size();

    for (int r=0; r<M; r++){
        update(p[r], 1);
        while(l<r && !check1()){
            update(p[l], 0);
            l++;
        }
        if (check2()){
            if (l==0) a = 1;
            else a = p[l-1]+1;
            if (r==M-1) b = 5000000;
            else b = p[r+1]-1;
            ans = max(ans, b-a);
        }
    }

    cout << ans << endl;

    return 0;
}