#include <bits/stdc++.h>

typedef long long ll;
typedef unsigned long long ull;

#define FOR(i,a,b) for(int (i)=(a);i<(int)(b);i++)
#define REP(i,n) FOR(i,0,n)
#define RANGE(vec) (vec).begin(),(vec).end()

using namespace std;

std::vector<int> sieve(int n) {
        std::vector<bool> is_prime(n+1);
        fill(is_prime.begin(), is_prime.end(), true);
        is_prime[0] = is_prime[1] = false;
        for (int i = 2; i <= n; ++i)
        {
            if ( is_prime[i] )
            {
                for (int j = 2*i; j <= n; j += i)
                    is_prime[j] = false;
            }
        }
        std::vector<int> ans;
        for (int i = 0; i < is_prime.size(); ++i)
        {
            if ( is_prime[i] )
                ans.push_back(i);
        }
        return std::move(ans);
}

class Yuki0012
{
public:
    void store(int x, vector<int> &use) {
            while (x)
            {
                use[x%10] = true;
                x /= 10;
            }
    }
    bool check(const set<int> &enable, vector<int> &use) {
            for (int i = 0; i < use.size(); ++i)
            {
                if ( use[i] && !enable.count(i) )
                    return false;
            }
            return true;
    }
    void solve(void)
    {
            int N;
            cin>>N;

            set<int> enable;
            REP(i,N)
            {
                int a;
                cin>>a;
                enable.insert(a);
            }
            auto primes = sieve(5000000);
            int  n = primes.size();

            int l,r;

            vector<int> cnt(10,0);
            int maxDiff = -1;
            l = r = 0;
            REP(i,n)
            {
                vector<int> use(10,0);
                store(primes[i], use);
                if ( !check(enable, use) )
                {
                    l = r = i+1;
                    fill(RANGE(cnt), 0);
                    continue;
                }
                REP(j, use.size())
                {
                    if ( !use[j] )
                        continue;
                    cnt[j]++;
                }
                int cn = 0;
                REP(j, cnt.size())
                {
                    if ( cnt[j] )
                        ++cn;
                }
                if ( cn == enable.size() )
                {
                    // [l,r)
                    int lower = primes[l];
                    int upper = primes[r];
                    if ( l > 0 )
                        lower = primes[l-1]+1;
                    if ( l == 0 )
                        lower = 1;
                    if ( r < primes.size()-1 )
                        upper = primes[r+1]-1;
                    if ( r == primes.size()-1 )
                        upper = 5000000;
                    maxDiff = max(maxDiff, upper-lower);
                }
                r = i+1;
            }
            cout<<maxDiff<<endl;
    }
};

#if 1
int main(int argc, char *argv[])
{
        ios::sync_with_stdio(false);
        auto obj = new Yuki0012();
        obj->solve();
        delete obj;
        return 0;
}
#endif