#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <numeric>
#include <cctype>
#include <tuple>
#include <climits>
#include <bitset>
#include <cassert>
#include <random>

#ifdef _MSC_VER
#include <agents.h>
#endif

#define FOR(i, a, b) for(int i = (a); i < (int)(b); ++i)
#define rep(i, n) FOR(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define REV(v) v.rbegin(), v.rend()
#define MEMSET(v, s) memset(v, s, sizeof(v))
#define UNIQUE(v) (v).erase(unique(ALL(v)), (v).end())
#define MP make_pair
#define MT make_tuple

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

const int N = 5e6+1;
int np[N];

int need[10];
int cnt[10];

bool can(){
	rep(i, 10) if (!need[i] && cnt[i]) return false;
	return true;
}

bool check(){
	rep(i, 10) if (need[i] != (cnt[i] >= 1)) return false;
	return true;
}

void f(int val, int k){
	if (!val) return;
	cnt[val % 10] += k;
	f(val / 10, k);
}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	for (int i = 2; i*i < N; ++i){
		if (!np[i]) for (int j = i * 2; j < N; j += i) np[j] = 1;
	}

	int n;
	cin >> n;
	rep(i, n){
		int x;
		cin >> x;
		need[x] = 1;
	}

	int l = 1, r = 1;
	int ans = -1;
	while (1){
		while (r < N && can()){
			if(check()) ans = max(ans, r - l - 1);
			if (!np[r]) f(r, 1);
			++r;
		}
		if (check()) ans = max(ans, r - l - 1);

		if (l >= r) break;

		if (!np[l]) f(l, -1);
		++l;
		if(check()) ans = max(ans, r - l - 1);
	}

	cout << ans << endl;

	return 0;
}