package no012;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		boolean[] use = new boolean[10];
		for(int i=0;i<n;i++) {
			use[sc.nextInt()] = true;
		}
		int[] digits = new int[10];
		ArrayList<Integer> primes = Sieve.primeList(5000000);
		int j = 0;
		int ans = -1;
		for(int i=0;i<primes.size();i++) {
			while(j <= primes.size()) {
				boolean expand = true;
				boolean ok = true;
				for(int k=0;k<10;k++) {
					if (!use[k] && digits[k] > 0) {
						expand = false;
						ok = false;
						break;
					}
					if (use[k] && digits[k] == 0) {
						ok = false;
					}
				}
				if (ok) {
					int k = i == 0 ? 1 : primes.get(i-1) + 1;
					int l = j == primes.size() ? 5000000 : primes.get(j) - 1;
					ans = Math.max(ans,l-k);
				}
				if (!expand) {
					break;
				}
				if (j == primes.size()) {
					break;
				}
				int p = primes.get(j);
				while(p > 0) {
					digits[p%10]++;
					p/=10;
				}
				//System.out.println(primes.get(i) + "," + primes.get(j));
				j++;
			}
			int p = primes.get(i);
			while(p > 0) {
				digits[p%10]--;
				p/=10;
			}
		}
		System.out.println(ans);
	}

}
class Sieve {
	public static boolean[] isPrimeArray(int max) {
		boolean[] isPrime = new boolean[max+1];
		Arrays.fill(isPrime, true);
		isPrime[0] = isPrime[1] = false;
		for(int i=2;i*i<=max;i++) {
			if (isPrime[i]) {
				int j = i * 2;
				while(j<=max) {
					isPrime[j] = false;
					j += i;
				}
			}
		}
		return isPrime;
	}
	public static ArrayList<Integer> primeList(int max) {
		boolean[] isPrime = isPrimeArray(max);
		ArrayList<Integer> primeList = new ArrayList<>();
		for(int i=2;i<=max;i++) {
			if (isPrime[i]) {
				primeList.add(i);
			}
		}
		return primeList;
	}
}