#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 7;

const int maxn = 5000001;
bool isprime[maxn];
vector<int> prime;
vector<int> digit;

int decomp(int n) {
	int res = 0;
	while (n) {
		res |= 1 << n % 10;
		n /= 10;
	}
	return res;
}

void sieve() {
	fill(isprime, isprime + maxn, true);
	for (ll i = 2; i < maxn; i++) {
		if (isprime[i]) {
			prime.push_back(i);
			digit.push_back(decomp(i));
			for (ll j = i * i; j < maxn; j += i) {
				isprime[j] = false;
			}
		}
	}
}

bool issubset(int a, int b) {
	return (a | b) == b;	
}

int main() {
	sieve();
	int N;
	cin >> N;
	int A = 0;
	rep (i, N) {
		int temp;
		cin >> temp;
		A |= 1 << temp;
	}

	int r = 0;
	int curr = 0;
	vector<int> num(10);
	int ans = -1;
	rep (i, prime.size()) {
		r = max(r, i);
		while (r < prime.size() && issubset(curr | digit[r], A)) {
			curr |= digit[r];
			rep (j, 10) {
				if (digit[r] >> j & 1) num[j]++;
			}
			r++;
		}

		if (curr == A) {
			int ub, lb;
			if (r == prime.size()) {
				ub = 5000000;
			} else {
				ub = prime[r] - 1;
			}
			if (i == 0) {
				lb = 1;
			} else {
				lb = prime[i - 1] + 1;
			}
			ans = max(ans, ub - lb);
		}

		curr = 0;
		rep (j, 10) {
			if (digit[i] >> j & 1) num[j]--;
			if (num[j] > 0) curr |= 1 << j;	
		}
	}

	cout << ans << endl;
}