using System; using System.Collections.Generic; using System.Linq; namespace No12{ public class Program{ public static void Main(string[] args){ var sr = new StreamReader(); //--------------------------------- var N = sr.Next(); var A = sr.Next(N); var pb = Prime.BitSieve(5000000); var cnt = 0; var hs = new HashSet(); var res = 0; for(var i = 1; i <= 5000000; i++){ cnt++; if(pb[i]){ foreach(var c in i.ToString()){ if(Array.IndexOf(A, c - '0') == -1){ hs.Clear(); cnt = 0; break; } hs.Add(c - '0'); } } if(A.Length == hs.Count){ res = Math.Max(res, cnt); } } Console.WriteLine(res - 1); //--------------------------------- } } public class Prime{ public static bool[] BitSieve(int n){ var sieve = new bool[n + 1]; for(var i = 2; i <= n; i++){ if(!sieve[i]){ for(var j = i << 1; j <= n; j += i) sieve[j] = true; } } return sieve.Select(b => !b).ToArray(); } } public class StreamReader{ private readonly char[] _c = {' '}; private int _index = -1; private string[] _input = new string[0]; private readonly System.IO.StreamReader _sr = new System.IO.StreamReader(Console.OpenStandardInput()); public T Next(){ if(_index == _input.Length - 1){ _index = -1; while(true){ string rl = _sr.ReadLine(); if(rl == null){ if(typeof(T).IsClass) return default(T); return (T)typeof(T).GetField("MinValue").GetValue(null); } if(rl != ""){ _input = rl.Split(_c, StringSplitOptions.RemoveEmptyEntries); break; } } } return (T)Convert.ChangeType(_input[++_index], typeof(T), System.Globalization.CultureInfo.InvariantCulture); } public T[] Next(int x){ var ret = new T[x]; for(var i = 0; i < x; ++i) ret[i] = Next(); return ret; } public T[][] Next(int y, int x){ var ret = new T[y][]; for(var i = 0; i < y; ++i) ret[i] = Next(x); return ret; } } }