#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <deque>
#include <array>
#include <numeric>
#include <bitset>
#include <iomanip>
#include <cassert>
#include <chrono>
#include <random>
#include <limits>
#include <iterator>
#include <functional>
#include <sstream>
#include <fstream>
#include <complex>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
using namespace std;

using ll = long long;
constexpr int INF = 1001001001;
constexpr int mod = 1000000007;
// constexpr int mod = 998244353;

template<class T>
inline bool chmax(T& x, T y){
    if(x < y){
        x = y;
        return true;
    }
    return false;
}
template<class T>
inline bool chmin(T& x, T y){
    if(x > y){
        x = y;
        return true;
    }
    return false;
}

struct ExtendedSieve{
    vector<int> table;
    const int n;

    ExtendedSieve(int n) : n(n) {
        table.assign(n + 1, 0);
        table[0] = table[1] = 1;
        for(int i = 2; i <= n; ++i){
            if(table[i] > 0)    continue;
            table[i] = i;
            for(int j = i + i; j <= n; j += i){
                if(table[j] == 0)   table[j] = i;
            }
        }
    }

    int operator[](const int& k){
        return table[k];
    }

    bool is_prime(int x){
        if(x < 2)   return false;
        return x == table[x];
    }

    map<int, int> prime_factorization(int x){
        map<int, int> res;
        while(x > 1){
            ++res[table[x]];
            x /= table[x];
        }
        return res;
    }
};

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

    int N, A;
    cin >> N;
    vector<bool> f(10);
    for(int i = 0; i < N; ++i){
        cin >> A;
        f[A] = true;
    }

    constexpr int MAX = 5000000;
    ExtendedSieve sieve(MAX);
    vector<vector<ll>> S(10, vector<ll>(MAX + 2));
    for(int i = 2; i <= MAX; ++i){
        if(!sieve.is_prime(i))  continue;
        int x = i;
        set<int> st;
        while(x > 0){
            st.emplace(x % 10);
            x /= 10;
        }
        for(auto num : st)  S[num][i + 1] = 1;
    }
    for(int i = 0; i < 10; ++i){
        for(int j = 0; j <= MAX; ++j){
            S[i][j + 1] += S[i][j];
        }
    }

    int lb = -1, ub = MAX;
    while(ub - lb > 1){
        int mid = (lb + ub) / 2;
        bool ok = false;
        for(int i = 0; i + mid + 1 <= MAX + 1; ++i){
            bool ok2 = true;
            for(int j = 0; j < 10; ++j){
                if(f[j]){
                    if(S[j][i + mid + 1] - S[j][i] == 0){
                        ok2 = false;
                        break;
                    }
                }
                else{
                    if(S[j][i + mid + 1] - S[j][i] > 0){
                        ok2 = false;
                        break;
                    }
                }
            }
            if(ok2){
                ok = true;
                break;
            }
        }
        if(ok)  lb = mid;
        else    ub = mid;
    }

    cout << lb << endl;

    return 0;
}