using System;
using System.Collections.Generic;

public class Program
{
    public void Proc() {
        Reader.IsDebug = false;
        // Console.WriteLine(DateTime.Now.ToString("HH:mm:ss.fff"));
        int numCount = int.Parse(Reader.ReadLine());
        this.RequireList.AddRange(Reader.GetInt());
        
        if(this.RequireList.Count == 10) {
            Console.WriteLine((MaxRange - 1).ToString());
            return;
        }
        
        this.CreatePrimeNumberList();
        
        Dictionary<int, int> countDic = new Dictionary<int, int>();
        int endIdx = 1;
        int startIdx = 0;
        int maxRangeIdxFrom = 0;
        int maxRangeIdxTo = 0;
        int maxRange = -1;
        while (startIdx < this.PrimeNumberList.Count)
        {
            countDic = new Dictionary<int, int>();
            if(!this.CountUp(PrimeNumberList[startIdx], countDic)) {
                startIdx++;
                continue;
            }
            endIdx = Math.Max(startIdx + 1, endIdx);
            if(endIdx >= this.PrimeNumberList.Count) {
                break;
            }
            for(int i=endIdx; i<this.PrimeNumberList.Count; i++) {
                if(!this.CountUp(PrimeNumberList[i], countDic)) {
                    int start = 1;
                    if(startIdx > 0) {
                        start = PrimeNumberList[startIdx - 1]+1;
                    }
                    int end = PrimeNumberList[i] - 1;
                    if(maxRange < end - start) {
                        bool hasNum = true;
                        this.RequireList.ForEach((num)=>{
                           if(!countDic.ContainsKey(num)) {
                               hasNum = false;
                           }
                        });
                        if(hasNum) {
                            maxRangeIdxFrom = startIdx;
                            maxRangeIdxTo = endIdx;
                            maxRange = end - start;
                        }
                    }
                    startIdx = i + 1;
                    break;
                } else
                {
                    endIdx = i;
                }
            }
        }
        if(endIdx >= this.PrimeNumberList.Count - 1) {
            int start = 1;
            if(startIdx > 0) {
                start = PrimeNumberList[startIdx - 1]+1;
            }
            int end = this.MaxRange;
            if(maxRange < end - start) {
                bool hasNum = true;
                this.RequireList.ForEach((num)=>{
                    if(!countDic.ContainsKey(num)) {
                        hasNum = false;
                    }
                });
                if(hasNum) {
                    maxRangeIdxFrom = startIdx;
                    maxRangeIdxTo = endIdx;
                    maxRange = end - start;
                }
            }
        }
        Console.WriteLine(maxRange);
        // Console.WriteLine(DateTime.Now.ToString("HH:mm:ss.fff"));
    }
    
    
    private Dictionary<int, List<int>> charDic = new Dictionary<int, List<int>>();
    private bool CountUp(int number, Dictionary<int, int> dic) {
        List<int> charList = null;
        if(this.charDic.ContainsKey(number)) {
            charList = this.charDic[number];
        } else
        {
            charList = new List<int>();
            foreach (char c in number.ToString())
            {
                int n = int.Parse(c.ToString());
                if(!charList.Contains(n)) {
                    charList.Add(n);
                }
            }
            this.charDic.Add(number, charList);
        }
        foreach (int item in charList)
        {
            if(!this.RequireList.Contains(item)) {
                return false;
            }
        }
        
        charList.ForEach((num)=>{
           if(dic.ContainsKey(num)) {
               dic[num]++;
           } else
           {
               dic.Add(num, 1);
           }
        });
        return true;
    }
    
    private void CreatePrimeNumberList() {
        bool[] flag = new bool[MaxRange + 1];
        for(int i=2; i<=MaxRange; i++) {
            if(!flag[i]) {
                this.PrimeNumberList.Add(i);
                int maxIdx = MaxRange / i;
                for(int j=1; j<=maxIdx; j++) {
                    flag[i*j] = true;
                }
            }
        }
    }
    
    private List<int> PrimeNumberList = new List<int>();
    
    private int MaxRange = 5000000;
    private List<int> RequireList = new List<int>();



    public class Reader {
        private static String InitText = @"

8
1 2 3 4 5 7 8 9


        ";
        
        private static System.IO.StringReader sr = null;
        
        public static bool IsDebug = true;
        
        public static string ReadLine() {
            if(IsDebug) {
                if(sr == null) {
                    sr = new System.IO.StringReader(InitText.Trim());
                }
                return sr.ReadLine();
            } else {
                return Console.ReadLine();
            }
        }
        public static int[] GetInt(char delimiter = ' ') {
            string[] inpt = ReadLine().Split(delimiter);
            int[] ret = new int[inpt.Length];
            for(int i=0; i<inpt.Length; i++) {
                ret[i] = int.Parse(inpt[i]);
            }
            return ret;
        }
    }
    public static void Main(string[] args)
    {
        Program prg = new Program();
        prg.Proc();
    }
}