#include <cstdio>
#include <algorithm>
#include <stack>
#include <queue>
#include <deque>
#include <vector>
#include <string>
#include <string.h>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <map>
#include <set>
#include <iostream>
#include <sstream>
#include <cctype>
#define fi first
#define se second
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rrep(i,n) for(int i = 1; i <= n; ++i)
#define drep(i,n) for(int i = n-1; i >= 0; --i)
#define gep(i,g,j) for(int i = g.head[j]; i != -1; i = g.e[i].next)
#define each(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define rng(a) a.begin(),a.end()
#define maxs(x,y) x = max(x,y)
#define mins(x,y) x = min(x,y)
#define pb push_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcount
#define snuke srand((unsigned)clock()+(unsigned)time(NULL));
inline int in() { int x; scanf("%d",&x); return x;}
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
typedef vector<int> vi;

const int MX = 5000000, INF = 1000010000;
const ll LINF = 1000000000000000000ll;
const double eps = 1e-10;
const int di[] = {-1,0,1,0}, dj[] = {0,-1,0,1}; //^<v>
//あのさぁ・・・
vector<int> ps; vector<bool> pf;
void sieve(int mx){
  pf.resize(mx+1); fill(rng(pf),true); pf[0] = pf[1] = false;
  for(ll i = 2; i <= mx; i++){
    if(!pf[i]) continue;
    ps.pb(i);
    for(ll j = i*i; j <= mx; j+=i) pf[j] = false;
  }
}

int n;
vi f;
void add(vi& a, int x, int val) {
  if (!pf[x]) return;
  while(x) {
    a[x%10] += val;
    x /= 10;
  }
}
bool ok(vi& a) {
  rep(i,10) if (!f[i] && a[i]) return false;
  return true;
}
bool all_use(vi& a) {
  rep(i,10) if (!f[i] && a[i]) return false;
  rep(i,10) if (f[i] && !a[i]) return false;
  return true;
}

int main(){
  cin >> n;
  f = vi(10);
  rep(i,n) {
    int a;
    cin >> a;
    f[a] = 1;
  }
  sieve(5000005);
  int ans = -1;
  vi nf = vi(10);
  for (int l = 1, r = 1; r <= MX; ++r) {
    add(nf,r,1);
    while (!ok(nf)) {
      add(nf,l,-1);
      ++l;
    }
    if (all_use(nf)) ans = max(ans,r-l);
  }
  cout << ans << endl;
  return 0;
}