#include <algorithm>
#include <iostream>
#include <string>
#include <vector>

int main() {
    using namespace std;
    constexpr int m = 5e6;
    vector<bool> is_prime(m + 1, true);
    is_prime[0] = false;
    is_prime[1] = false;
    for (int i = 2; i <= m / i; i++) {
        if (!is_prime[i]) { continue; }
        for (int j = i * i; j <= m; j += i) { is_prime[j] = false; }
    }

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

    vector<int> count(10, 0);
    int r = 1, nums = 0, ans = -1;
    for (int l = 1; l <= m; l++) {
        if (r < l) {
            r = l;
            for (int i = 0; i < 10; i++) { count[i] = 0; }
            nums = 0;
        }
        while (r <= m) {
            if (is_prime[r]) {
                bool ng = false;
                for (auto c : to_string(r)) {
                    int nc = c - '0';
                    if (!(req >> nc & 1)) { ng = true; }
                }
                if (ng) { break; }
                for (auto c : to_string(r)) {
                    int nc = c - '0';
                    if (count[nc]++ == 0) { nums |= 1 << nc; }
                }
            }
            r++;
        }
        if (nums == req) { ans = max(ans, r - l - 1); }
        if (is_prime[l]) {
            for (auto c : to_string(l)) {
                int nc = c - '0';
                if (--count[nc] == 0) { nums ^= 1 << nc; }
            }
        }
    }
    cout << ans << endl;
}