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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int Need = 5000000;
    vector<int> allp;
    vector<bool> prime(Need+1,true);
    prime.at(0) = false; prime.at(1) = false;
    for(int i=2; i<=Need; i++){
        if(!prime.at(i)) continue;
        allp.push_back(i);
        for(long long k=((long long)i)*i; k<=Need; k+=i) prime.at(k) = false;
    }
    
    int n = allp.size();
    vector<int> use(n);
    for(int i=0; i<n; i++){
        int p = allp.at(i);
        int now = 0;
        while(p) now |= (1<<(p%10)),p /= 10;
        use.at(i) = now;
    }
    vector<vector<int>> next(n,vector<int>(10,n));
    for(int i=n-1; i>=0; i--){
        for(int k=0; k<10; k++){
            if(use.at(i)&(1<<k)) next.at(i).at(k) = i;
            else if(i != n-1) next.at(i).at(k) = next.at(i+1).at(k);
        }
    }

    int N; cin >> N;
    int A = 0;
    while(N--){
        int a; cin >> a;
        A += 1<<a;
    }

    allp.push_back(5000001);
    int answer = -1;
    for(int i=0; i<n; i++){
        int one = -1,two = n;
        for(int k=0; k<10; k++){
            if(A&(1<<k)) one = max(one,next.at(i).at(k));
            else two = min(two,next.at(i).at(k));
        }
        if(one >= two) continue;
        if(i == 0) answer = max(answer,allp.at(two)-1-1);
        else answer = max(answer,allp.at(two)-1-(allp.at(i-1)+1));
    }

    cout << answer << endl;
}