#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

#define REP(i,s,e) for (i = s; i <= e; i++)
#define rep(i,n) REP (i,0,(int)(n)-1)
#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP (i,(int)(n)-1,0)
#define INF (int)1e8
#define MOD (int)(1e9+7)

typedef long long ll;

bool prime[5000001];

int main(void) {
    int i, j;
    for (i = 2; i <= 5000000; i++) prime[i] = true;
    for (i = 2; i * i <= 5000000; i++) if (prime[i]) {
        for (j = i*2; j <= 5000000; j+=i)
            prime[j] = false;
    }

    int n;
    int req = 0;
    cin >> n;
    rep (i,n) {
        int a;
        cin >> a;
        req |= 1<<a;
    }

    int nums[10] {};
    int l, r;
    int ans = -1;
    l = 1; r = 2;
    while (r <= 5000000) {
        int x = r;
        while (x) {
            nums[x%10]++;
            x /= 10;
        }
        do {
            r++;
        } while (!prime[r] && r <= 5000000);
        r--;
        while (l <= r) {
            bool ok = true;
            rep (i,10) {
                if ((req & 1<<i) && nums[i] == 0)
                    break;
                else if ((req & 1 << i) == 0 && nums[i] > 0)
                    ok = false;
            }
            if (i < 10) break;
            if (!ok) {
                while (!prime[l] && l <= 5000001) l++;
                int x = l;
                while (x) {
                    nums[x%10]--;
                    x /= 10;
                }
                l++;
            }
            else {
                ans = max(r - l, ans);
                break;
            }
        }
        r++;
    }
    cout << ans << endl;
    return 0;
}